Cosmos Works Tutorials

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Power • Accuracy • Functionality

V E R S I O N

6.0

T u t o r i a l s

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1999 Structural Research and Analysis Corporation (SRAC) 12121 Wilshire Blvd., Suite 700 Los Angeles, California 90025-1170 310 207-2800 (phone) 310 207-2774 (fax)

COSMOS/M, COSMOS/Works, and GEOSTAR are trademarks of Structural Research and Analysis Corporation. ANSYS is a trademark of SAS IP. MSC and MSC/are registered trademarks of MacNeal-Schwendler Corporation.

Information is subject to change without notice. No material may be reproduced or transmitted in any form or by any means for any purpose without written permission of SRAC.

NASTRAN is a registered trademark of the National Aeronautics and Space Administration.

As a condition to your use of this software, you agree to accept the limited warranty, disclaimer and other terms and conditions set forth in SRAC License Agreement which accompanies this software. If, after reading the SRAC License Agreement, you do not agree with its terms and conditions, promptly return the unused software and all accompanying material to SRAC and your payment will be refunded.

IGES Access Library is a trademark of IGES Data Analysis, Inc. Other brand or product names are trademarks or registered trademarks of their respective holders.

Acrobat, and Acrobat Reader are trademarks of Adobe Systems Incorporated.

Portions of this software® 1999 Unigraphics SolutionsTM, Inc. Portions of this software® 1999 Visual Kinematics, Inc. Portions of this software® 1999 Solversoft, Inc.

1 Introduction

This manual provides you with step-by-step tutorials to use COSMOS/Works. These tutorials assume that you are familiar with SolidWorks. The tutorials are grouped as follows

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Static Analysis Tutorial Contact Stress Analysis Tutorial Importing Motion Loads Frequency Analysis Tutorial Buckling Analysis Tutorial Thermal Analysis Tutorial Optimization Analysis Tutorial

Although you can begin with the tutorials, we recommend that you read the COSMOS/Works Fundamentals, COSMOS/Works Interface, and Analysis Background chapters of the COSMOS/Works User’s Guide to familiarize yourself with some of the fundamentals, including:

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Design Study Concepts The COSMOS/Works Manager, and COSMOS/Works Analysis Capabilities

Learning to Use COSMOS/Works

1-1

✍ Structural Research and Analysis Corporation continuously updates the COSMOS/Works program to improve accuracy and performance. Please note that when you try the tutorials in this manual, you may obtain slightly different results depending on the version of SolidWorks and COSMOS/ Works installed on your computer.

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COSMOS/Works Tutorial

2 Static Analysis Tutorial

This chapter presents step-by-step lessons for performing linear static analysis.

q q q q q q q q

Lesson 1: Analysis of a Bracket Part Lesson 2: Analysis of a Crank Assembly Lesson 3: Analysis of a Thin Bracket (Shell Model) Lesson 4: Analysis of an I-beam (Shell Model) Lesson 5: Analysis of a Funnel (Shell Model) Lesson 6: Analysis of a Fuel Storage Tank (Shell Model) Lesson 7: Analysis of a Pulley Under a Bearing Force Lesson 8: Stress Concentration Around a Hole in a Plate


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Chapter 2 Static Analysis Tutorial

n Lesson 1: Analysis of a Bracket Part

Lesson 1: Analysis of a Bracket Part In this lesson, you will learn how to:

q q q q q q q

Retrieve a part and create a static analysis study, Assign material to the part, Insert restraints and pressure loading, Mesh the part, Run static analysis, Use COSMOS/Works menu system and new toolbars to perform analysis steps, and Visualize the static analysis results.

Retrieve the Part To retrieve the part:

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1

Start COSMOS/Works.

2

Click File, Open. The Open dialog box opens.

3

Change the Look in folder to ...\Examples where “...” refers to the COSMOS/Works installation directory.

4

From the Files of type drop-down list, select Part Files (*.prt; *.sldprt).

5

Double-click the Tutor1.prt file. The part opens.

✍ If you do not see the COSMOS/Works menu in the SolidWorks menu bar, click Tools, Add-ins, then click the COSMOS/Works checkbox and click OK. To set the unit options: 1

Click Tools, Options. The System Options-General dialog box opens.

2

On the Document Properties tab, click Units.

3

From the Linear units menu select Millimeters.

4

Click OK.

✍ We recommend that you use File, Save As to save the part to a different name before defining a study so that you can use the original file again.

Create a Static Analysis Study The first step in performing analysis with COSMOS/Works is to create a design study. You can use the COSMOS/Works Manager or the menu system to create and manage studies. We will use the COSMOS/Works Manager to manage all aspects related to design analysis studies.


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To start the COSMOS/Works Manager: Click the COSMOS/Works Manager icon located at the lower left corner of the window.

COSMOS/Works Manager

✍ To return to the normal FeatureManager design . tree, click the FeatureManager icon To create a static analysis study: 1

In the COSMOS/Works Manager, right-click the Tutor1 part icon and select Study, - or From COSMOS/Works menu, select Study, - or Click the Study button Works Main toolbar.

on COSMOS/

The Study dialog box opens. 2

Click the Add button. The Study Name dialog box opens.

3

In the New Study field, type in the name of the study, for example, Static-1.

4

From the Analysis Type drop-down list, choose Static (default).

5

In the Mesh Type box, click the Solid button.

6

Click OK. The study name appears in the Studies list box.

7

Click OK.

To set the properties of the static study:

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1

In the COSMOS/Works Manager, right-click the Static-1 study icon and select Properties. The Static dialog box opens.

2

In the Solver box, make sure that FFE is selected.

3

Click OK.

Preprocessing Assign Material To assign a material from the COSMOS/M Library: 1

In the COSMOS/Works Manager tree, right-click the Tutor1 icon under Solids folder and select Apply/Edit Material, - or From COSMOS/Works menu, click Apply Material to All, - or Click the Apply Material to All button toolbar.

on the COSMOS/Works Main

The Material dialog box opens with the COSMOS/M Library tab selected. 2

From the Material Type drop-down menu, verify that Steel is selected.

3

In the Material Name list box, verify that Alloy Steel is selected.


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4 Optional: From the Unit System

drop-down menu, click the desired system of units to use in displaying the material properties. ✍ In general, you can use any system of units regardless of the units you used to create the model. 5 Optional:

From the Property Type drop-down menu, choose All, Structural, or Thermal. Only structural or thermal properties will be listed if you select Structural or Thermal, respectively. ✍ The Unit System option is used for display convenience only when you select a material from the library. It does not change the actual values or affect the results. The proper unit system must be selected if you choose to input values for material properties manually.

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6

Click OK. COSMOS/Works assigns Alloy Steel to the part. A checkmark appears on the part icon.

7

To list the properties of the applied material, right-click the Tutor1 icon under the Solids icon and click Details. The material information is listed in the Details window.

Insert Loads and Boundary Conditions For static analysis, you must apply sufficient restraints to stabilize the part and apply at least one type of loading. In this example, we will fix the two holes in the part’s base and apply pressure normal to the front face of the cylinder.

Apply pressure normal to this face Fix these holes

To fix the two holes: 1

Select the face of one hole. Press and hold down the Ctrl key and select the face of the other hole. The two faces highlight as shown in the figure.

2

In the COSMOS/Works Manager tree, right-click the Load/Restraint icon and select Restraints, - or From COSMOS/Works menu, select Insert, Restraints, - or Click the Restraint button

on COSMOS/Works Loads toolbar.

The Restraints dialog box opens.


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3


From the Type box, select Immovable.

4 Optional:

To change the color of the restraint symbol, click the Color button. The Color palette opens. Select the desired color and click OK.

5

Click OK. Restraints are applied to the selected spotted faces and displayed in the selected color.

To apply uniform pressure: 1

Select the front face of the cylinder. The face highlights.

2

In the COSMOS/Works Manager tree, right-click the Load/Restraint icon and select Pressure, - or From COSMOS/Works menu, click Insert, Pressure, - or Click the Pressure button

on COSMOS/Work Loads toolbar.

The Pressure dialog box opens.

2-8

3

In the Type box, click the Normal to selected face button.

4

In the Distribution box, make sure that Uniform is selected.

5

From the Units menu, select English (IPS).

6

In the Value field, enter 1000 to apply 1000 psi.

✍ Although the unit of length for the model is millimeters, you can choose to specify pressure in any other system of units. ✍ You can view the value of the applied pressure in other units by changing the unit field. 7

Click OK. The pressure is applied.

✍ You can edit the definition of any load or boundary condition by rightclicking the corresponding icon in the COSMOS/Works Manager tree.

Mesh the Part The meshing process prepares the model for the numerical solution. The quality of the mesh controls the quality of the results. We will use high quality mesh for this part.


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To set mesh preferences: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and select Preferences. The Preferences dialog box opens with the Mesh tab selected.

2

In the Mesh Quality box, select High.

3

In the Mesh Control box, select Smooth Surface.

4

In the Mesher Type box, select Standard.

5

From the Jacobian Check menu, make sure that 4 Points is selected.

6

Click OK.

To mesh the part: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and select Create. - or From COSMOS/Works menu, click Mesh, Create, - or Click the Mesh button

on COSMOS/Works Main toolbar.

The Mesh dialog box opens and an average element size is suggested. You can change the element size by typing in its field or using the slider. A finer mesh gives more accurate results but requires more computer resources and takes more time to solve. In this example, however, we will use the default element size.

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2

Click OK. The Mesh Progress window opens and the program starts meshing. After the mesh is completed, the Solid Mesh completed message appears.

3

Click OK. Notice the checkmark that appears on the Mesh icon.

To view the mesh: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and select Show Mesh. The mesh is displayed in the SolidWorks window.

2

Right-click the Mesh icon again and select Hide Mesh to hide the mesh.

3

Right-click the Mesh icon and select Details to display information about the mesh: global element size, tolerance, quality option, and the number of nodes and elements

You are now ready to run the analysis.


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Run Static Analysis To run static analysis: 1

In the COSMOS/Works Manager tree, right-click the Static-1 study icon and select Run, - or From COSMOS/Works menu, select Run, - or Click the Run button

on COSMOS/Works Main toolbar.

Analysis starts. When the analysis is completed, you will get the Static Analysis Completed message. 2

Click OK.

Postprocessing Static Results COSMOS/Works provides advanced high quality rendering and visualization tools as an option during result visualization. You can switch to the Standard result visualization scheme which is useful in the case of very large models. To calculate the reaction forces on the faces of the two holes: 1 Hide the restraint and pressure symbols by right-clicking the Load/Restraint folder and selecting Hide All. 2

Select the faces of the two holes as shown in figure.

3

In the COSMOS/Works Manager, rightclick the Displacement folder and select Reaction Force. The Reaction Force dialog box opens.

4

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From the Units menu, select lb. The sum of the reaction forces on the selected faces and on the entire model will be listed in the selected unit.

Select these faces

To verify the results of the reaction force, multiply the area of the circular face (2.8389 in 2 ) by the applied pressure (1000 psi) to get the reaction force on the entire model. To calculate the reaction forces on the vertical face:

Select this face

1

Select the vertical face of the bracket.

2

Right-click the Displacement folder and select Reaction Force .

3

In the Reaction Force dialog box, change the Units field to lb. The sum of the reaction forces on the selected face will be listed. Note that the listed values are all zeros as expected.

To calculate the reaction forces on the bottom face of the bracket: 1

Select the bottom face of the bracket.

2

Right-click the Displacement folder and select Reaction Force.

3

In the Reaction Force dialog box, change the Units field to lb. The reaction force components will be listed. Note that the reaction force components in the X, Y, and Z directions are not zeros. This is due to the fact that the edges of the two holes are contributing to the reaction force on that face.


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✍ If you select the edges of the two holes and calculate the reaction forces, you should obtain the same values as those obtained when you select the bottom face.

Select this face

To set result visualization (Graphics) option: 1

Click COSMOS/Works, Preferences. The Preferences setting box opens.

2

Click the Graphics tab.

3

In the Display box, click the Advanced button.

4

Click OK.

Built-in Standard Plots von Mises Stress Plot

Von Mises stresses are calculated from stress components in various directions. They give an overall picture of the stress. Refer to the Analysis Background chapter for more details. To plot von Mises stresses: 1

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In the COSMOS/Works Manager tree, click the (+) sign to the left of the Stress folder. The Plot1 icon appears in the Stress folder.

2

Double-click the Plot1 icon. ✍ By default, the stresses are plotted on the deformed shape.

To set the color map of the plot: 1

In the COSMOS/Works Manager tree, right-click the Plot1 icon and select Color Map. The Color Map dialog box opens. The Color Map dialog box gives you 4 options, Default, Rainbow, Gray Scale, and User-defined.

2

Make your selection and click OK. ✍ If you select the User-defined option, you will need to specify the number of colors you want to use. You can use up to 9 base colors. To change or define a color, click its box, and choose a color from the color palette.

To change the stress units: 1

In the COSMOS/Works Manager tree, right-click the Plot1 icon in the Stress folder and select Edit Definition. The Stress Plot dialog box opens with the Properties tab selected.

2

From the Stress Units menu, select the desired units and click OK.

To animate the stress plot: 1

In the COSMOS/Works Manager tree, right-click the Plot1 icon in the Stress folder and select Animate. The Animation dialog box opens.

2

Click the right arrow button animation.

3

Click the square button

4

Close the Animation dialog box.

to start the to stop the animation.

✍ You can save your animation as an AVI movie file by checking the Save As AVI checkbox.


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To view an AVI file with Media Player: 1

In the Animation dialog box, check Save As AVI file.

2

Check View with Media Player and click Browse to specify the path and name of the file.

3

Click . The Video Compression dialog box opens.

4

Accept the defaults and click OK.

Equivalent Element Strain Plot

The equivalent element strains are calculated from strain components in various directions. Refer to the Analysis Background chapter for the definition of the equivalent element strain. To generate the equivalent element strain plot: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Strain folder. The Plot1 icon appears.

2

Double-click the Plot1 icon.

Resultant Displacement Plot

Resultant displacements are calculated from displacement components in various directions.

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To generate the resultant displacement plot: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Displacement icon. The Plot1 icon appears.

2


Deformation Plot

To generate the deformed shape plot: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Deformation icon. The Plot1 icon appears.

2



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Section Plot

To generate a section plot of the first principal stress:

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1

In the COSMOS/Works Manager tree, right-click the Stress folder and select Define. The Stress Plot dialog box opens.

2

Click the Display tab.

3

From the Result Type box, click Node Values.

4

In the Plot Type box, click Section.

5

From the Fringe Type drop-down list, click Filled, Discrete.

6

In the No. of Sections field, type in 1.

7

From the Component drop-down list, click P1: Normal Stress (1st principal).

8

Click OK. The section plot is generated and a new icon (Plot2) appears in the Stress folder of the study.

To control the section plot: 1

In the COSMOS/Works Manager, right-click the Plot2 and select Clipping. The Section Clipping dialog box opens.

2

In the Uncut field, select Fringe.

3

In the Cut Direction field, select Outside.

4

Click the Sensitive checkbox.

5

Drag the sliders to modify the distance and orientation of the section.

6

Click OK.

To change the cutting tool (primitive) for the section plot: 1

Right-click the Plot2 icon in the Stress folder and click Edit Definition.

2


3

Double-click the 0 Plane: in the cutting tool list box. The primitive selection menu opens.


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4

Click the desired primitive (Plane, Cylinder, or Sphere).

5

Click OK.

To generate a default design check plot: 1

Click the (+) sign next to the Design Check folder. The Plot1 icon appears.

2

Double-click the Plot1 icon, the Design Check Wizard Step 1 of 3 window opens.

3

Click the Maximum von Mises stress button.

4

Click Next. The Design Check Wizard Step 2 of 3 window opens.

5

In the Set stress limit box, click the to Yield strength button.

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6

Click Next. The Design Check Wizard Step 3 of 3 window opens.

7

Click the Areas below factor of safety button and enter a value of 1 in the field next to it.

8

Click Finish. Regions with a factor of safety less than 1 (unsafe regions) will be shown in red.

Unsafe regions


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Printing Plots To print a plot: 1

In the COSMOS/Works Manager tree, right-click the icon of the plot you want to print and select Print. The Print dialog box opens.

2

Set your printing options and click OK.

Saving Result plots: To save a plot as a BMP or VRML file: 1

In the COSMOS/Works Manager, double-click the icon of the plot.

2

Right-click the plot icon and select Save As. The Save As dialog box opens.

3

In the Save in field, specify the folder where the plot is to be saved.

4

In the File name field, enter a name for the plot.

5

In the Save as type field, select VRML files (*.wrl), Bitmap files (*.bmp), XGL files (*.xgl), or ZGL (*.zgl) files.

6

Click Save.

Generating a Report for the Study The Report utility provides an excellent way for reviews by colleagues and supervisors as well as placement on web sites. 1 Click COSMOS/ Works, Report. The Report setting box opens.

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2

Click the desired section in the Settings for list box for a preview of its contents.

3

Click Set to enter or modify its contents. The corresponding Set dialog box opens.

4

Specify the desired information or make the desired change.

5

Click OK.

6

Repeat steps 2 through 5 for other sections. You can insert bitmap images, AVI movies, and VRML files in the appropriate sections.

7

Click OK.

This lesson is completed.


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n Lesson 2: Analysis of a Crank Assembly

Lesson 2: Analysis of a Crank Assembly In this lesson, we will analyze the crank subassembly shown below. This subassembly contains 4 components (parts) as follows:

q q q

Crank Pulley, Crank Arm Axle, and Two Crank Arms.

In this lesson, you will learn how to:

q q q q q 2-24

Retrieve the assembly, Create a static analysis study, Assign materials to the various components of the assembly, Insert restraints and loads, Mesh the assembly,

q q q q q q

Run static analysis, Visualize the static analysis results, Create a frequency analysis study, Copy materials, restraints, and loads from the static analysis study, Run frequency analysis, and Visualize frequency analysis results.

✍ A special authorization (intermediate configuration) is required to work with assemblies.

Retrieve the Assembly To retrieve the assembly: 1

Start SolidWorks.

2


3

Change the Look in folder to ...\Examples where “...” refers to the COSMOS/ Works installation folder.

4

From the Files of type field, select Assembly Files (*.asm; *.sldasm).

5

Check the Preview checkbox.

6

Double-click the Crank.ASM assembly file. The Crank assembly opens.


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✍ If you do not see the COSMOS/Works menu, click Tools, Add-ins, then check the control box for COSMOS/Works and click OK.

To set the unit of length: 1

Click Tools, Options. The System Options-General dialog box opens.

2

On the Document Properties tab click Units.

3

From the Linear units menu select Inches.

4

Click OK. ✍ We recommend that you click File, Save As to save the part to a different name before defining a study so that you can use the original file again.

Analysis of assemblies in COSMOS/Works is simple and straightforward. The steps required to analyze an assembly are identical to those required to analyze a part except for the option to apply different materials to different components.

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To start the COSMOS/Works Manager: COSMOS/Works Manager

Click the COSMOS/Works Manager toggle icon located at the lower left corner of the SolidWorks window.

Create a Static Analysis Study 1

Right-click the Crank icon and select Study. The Study dialog box opens.

2

Click Add. The Study Name dialog box opens.

3

In the New Study field, type in the name of the study, for example, Initial.

4

From the Analysis Type drop-down list, select Static (default).

5

In the Mesh Type box, click Solid.

6


7

Click OK to close the Study dialog box.

Define Material for Each Component In the assembly environment, the Solids folder contains an icon for each component (part) of the assembly. The name of the part appears next to the corresponding material icon. You can assign a different material to each part, or one material to all parts at once.


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To assign a material to the CrankArm Axle part: 1

In the COSMOS/Works Manager tree, right-click CrankArm Axle-1 in the Solids folder and select Apply/Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type drop-down list make sure that Steel is selected.

3

From the Material Name list box, select Stainless Steel (ferritic).

4

Click OK. The selected material will be assigned to the CrankArm Axle part.

To assign materials to the other parts: Repeat the steps above to assign Gray Cast Iron to CrankPulley1, and Alloy Steel to CrankArm-1 and CrankArm-2. ✍ If you have an assembly with the majority of the parts made of the same material, you can apply the following procedure:

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1

Assign this material to all parts by right-clicking the Solids folder and selecting Apply Material to All.

2

Edit the material definition for each part with a different material by rightclicking its icon and selecting Apply/Edit Material.

Apply Loads and Restraints We will fix the outer face of the pulley, and apply a force in the negative Xdirection to the face of one of the pedals.

Apply a force to this face in the negative X-direction

Fix this face

To fix the outer face of the pulley: 1

Select the outer cylindrical face of the pulley. The face highlights.

2

Right-click Load/Restraint folder and select Restraints. The Restraints dialog box opens.

select this face


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3

In the Type box, select Immovable (No Translation).

4

Click OK.

To apply uniform force to one of the pedals: 1

Select the face of the pedal of CrankArm-2. The face highlights as shown.

2

Right-click the Load/Restraint folder and select Force. The Force dialog box opens.

select this face

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3

In the Type box, click Apply Force/Moment.

4

From the Distribution box, make sure that Uniform is selected.

5

From the Units drop-down list, select English (IPS).

6

Click the Along Plane Dir1 checkbox.

7

In the Value field, enter -200 (pounds).

8

Click OK. The total force is applied.

Mesh the Assembly The whole assembly is meshed at once. To set mesh preferences: 1

Right-click the Mesh icon and select Preferences. The Preferences dialog box opens with the Mesh tab selected.

2

In the Mesh Quality box, click High.

3


4


5

In the Jacobian Check field, make sure that 4 Points is selected.

6

Click OK.

To mesh the assembly: 1

Right-click the Mesh icon and select Create.

2

In the Global Size field, enter 0.6 (inches).

3

Click OK. The Mesh Progress window opens and the program starts meshing the parts one by one.


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To Show/Hide the mesh: 1

Right-click the Mesh icon, and select Show Mesh . The mesh is displayed as shown.

2

Right-click the Mesh icon again and click Hide Mesh to hide the mesh, - or Click the Show/Hide Mesh button Works Main toolbar.

3

on COSMOS/

Right-click the Mesh icon and select Details to display information about the mesh: global element size, tolerance, quality option, and the number of nodes and elements.


Right-click the Initial study icon and click Run. The analysis starts. When the analysis is completed, you will get the Static Analysis Completed message.

2

Click OK.

Visualize the Results of Static Analysis COSMOS/Works gives you the option to use the Standard or the Advanced graphics for result visualization. To set the graphics option: 1

Click COSMOS/Works, Preferences. The Preferences dialog box opens.

2

Click the Graphics tab.

3

In the Display box, click Advanced.

4

Click OK. ✍ Use the Standard option for very large models.

von Mises Plot To visualize von Mises Stresses: 1

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In the COSMOS/Works Manager tree, click the (+) sign to the left of the Stress folder. The plot1 icon appears.

2

Double-click the Plot1 icon. The von Mises stress plot is generated.

3

To change the display units of the stress, right click the Plot1 icon and select Edit Definition. The Stress Plot dialog box opens.

4

On the Properties tab, select psi from the Stress Units menu.

To animate the stress plot: 1 2

Right-click the Plot1 icon and select Animate. To save the animation as an AVI file, check the Save as AVI File box.

3

To start the animation, click the play button

4

To stop the animation, click the stop button

5


. .

To change the color map for the stress plot: 1

Right-click the Plot1 icon and click Color Map. The Color Map dialog box opens.

2

From the drop-down list select a color map. The available color maps are: Default, Rainbow, Gray Scale.

3

Enter the desired number of chart colors you want to use in the plot.

4

After making your choice, click Apply to see the effect dynamically.


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5


Click OK.

To create your own color map: 1

Right-click the Plot1 icon and select Color Map. The Color Map dialog box opens.

2

From the drop-down list select User Define .

3

Enter the number of colors you want to use in the plot.

4

Choose the colors you want to use. To change a color, click its box and select the desired one from the color palette.

5

Click OK.

Section Plots To generate a section plot:

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1

In the COSMOS/Works Manager tree, right-click the Stress folder and select Define.

2


3


4


5

From the Fringe Type drop-down list, select Filled, Tone.

6

From the No. of Sections menu, click the spin box to specify a number of sections, for example, 3.

7

Double-click 0 Plane: in the list box to select a cutting tool, for example, Cylinder.

8

Repeat step 6 for 1 Plane and 2 Plane.

9

Click OK. The section plot is generated.

To control the Section plot: 1

Double-click the Plot2 icon under the Stress folder.

2

Right-click the Plot2 icon in the COSMOS/Works Manager and select Clipping. The Section Clipping dialog box opens.

3

From the Uncut Part drop-down list, select Fringe.

4

From the Cut Direction drop-down list, select Both.

5

Check the Sensitive checkbox.

6

Modify the sections as desired using the sliders. To modify a section, click its tab and drag the Radius and Center sliders.

7

Click OK.


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Vector Plot To generate a vector plot:

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1

In the COSMOS/Works Manager tree, right-click the Stress folder and select Define. The Stress Plot dialog box opens.

2

Click Display tab.

3

In the Plot Type box, click Vector.

4

From the Fringe Type drop-down list, select Filled, Discrete.

5

In the Component list box, select P1: Normal stress (1st principal).

6

Click OK.

Generating a Report for the Study To generate a report: 1

In the COSMOS/Works Manager, right-click the Initial study icon and select Report. The Report dialog box opens.

2

Click a section in the Settings for list box to preview its contents.

3

Click Set. The corresponding Set dialog box opens.

4

Edit the contents as desired and click OK.

5

Repeat steps 2-3 for other sections of the report.

6

For the result sections of the report, you may add AVI files, and image files as desired.



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n Lesson 3: Analysis of a Thin Bracket (Shell Model)

Lesson 3: Analysis of a Thin Bracket (Shell Model) In this lesson, you will learn how to:

q q q q q q

Open a part and create a static analysis study (shell elements), Assign material to the part, Insert restraints and pressure loading, Mesh the part with shell elements, Run static analysis, and Visualize the static analysis results.

Open the Part To open the part: 1


2


3

From the Files of type dropdown list, select Part Files (*.prt; *. sldprt).

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4

Double-click the sheet.prt file.

5

Verify that COSMOS/Works appears in the top menu bar of SolidWorks.

✍ If you do not see the COSMOS/Works menu, click Tools, Add-Ins. Check the COSMOS/Works checkbox and click OK. To verify the units: 1

On the SolidWorks menu bar, click Tools, Options.

2


3

Make sure that Inches appears from the Linear units drop-down menu.

4

Click OK. ✍ At this point, we recommend that you click File, Save As to save the part with a different name before defining a study so that you can use the original file again.

Before performing the analysis with COSMOS/Works, we will scale the part down by a factor of 0.1. To scale the part: 1

Click Insert, Features, Scale. The Scale dialog box opens.

2

In the Type box, make sure that Centroid appears in the About menu.

3

Make sure also that the Uniform box is checked.

4

In the Scaling factor field, type 0.1.

5

Click OK. The model will be scaled down by the specified factor.

To restore the normal view of the model, click the Zoom to Fit tool View toolbar.

on the

Create a Static Analysis Study The first step in performing analysis with COSMOS/Works is to create a design study. We will use the COSMOS/Works Manager to manage all aspects related to design analysis studies. Equivalent commands are available in the pull-down menus. To start the COSMOS/Works Manager: Click the COSMOS/Works Manager button located at the lower left corner of the window. Learning to Use COSMOS/Works

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To create a static analysis study: 1

Right-click the Sheet part icon and select Study. The Study dialog box opens.

2


3

In the New Study field, type in Shell as the name of the new study.

4

From the Analysis Type drop-down list, select Static (default).

5

In the Mesh Type box, click the Shell using midsurfaces button. The program displays a message about the limitations of shell modeling in this version.

6

Read the message and click OK.

7


8

Click OK.

Set the Properties of the Study To set the properties of the study: 1

Right-click the study icon and select Properties. The Static dialog box opens.

2

In the Solver box, make sure that FFEPlus is selected.

3

Click OK. ✍ FFE does not support high-order shells. If you choose FFE, the program will automatically switch to FFEPlus.

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Assign Material To assign a material from the COSMOS/M Library: 1

Right-click the Sheet icon in the Solids folder and select Apply/Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected

2

From the Material Type drop-down list, verify that Steel is selected.

3

From the Material Name list box, verify that Alloy Steel is selected.

4

From the Unit System drop-down list, click the desired system of units to use it in displaying the properties.

5

From the Property Type drop-down list, choose All.

6

Click OK. The material is assigned to the part and a checkmark appears on the Sheet icon in the Materials folder.

7

To verify the material assignment, right-click the Sheet icon and select Details.

.


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Insert Loads and Restraints We will fix the three holes and apply pressure to the bottom plate. To insert restraints: 1

Select the face of any hole. You can use the Zoom In tool to make sure you select the proper face.

2

Hold down the Ctrl key and select the faces of the other holes. The selected faces should highlight as shown in the figure.

3

In the COSMOS/Works Manager tree, right-click the Load/Restraint folder and select Restraints. The Restraints dialog box opens.

✍ Notice that the Selected Entities box lists the number of selected faces, edges and vertices. In this case, 3 faces are selected. 4

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From the Type box, verify that Fixed is selected to set all translations and rotations to zero.

✍ The Immovable option sets the translations to zero while the Fixed option sets both translations and rotations to zero. 5 Optional:

To change the color of the restraint symbol, click the Color button. The Color palette opens. Select the desired color and click OK.

✍ The Units option is irrelevant when selecting Immovable or Fixed. 6

Click OK.

To insert uniform pressure: 1

Select the face of the model shown in the figure.

2

In the COSMOS/Works Manager tree, right-click the Load/Restraint and select Pressure. The Pressure dialogue box opens.

Select this face

✍ Notice that the Selected Entities box lists one selected face. 3

In the Type box, click Normal to selected face to apply pressure normal to the selected face.

4



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5


6

In the Value field, enter 1.00 to apply 1.00 psi.

✍ You can list the value of the applied pressure in other units by changing the unit field. 7


Mesh the Part The meshing process prepares the part for the numerical solution. The quality of the mesh controls the quality of the results. To set mesh preferences: 1


2

From the Mesh Quality box, click High.

3

In the Mesh Control, check Smooth Surface and uncheck Automatic Transition.

4


5

From the Jacobian Check drop-down menu, select 4 Points (default).

6

Click OK.

To mesh the part: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and select Create. The Mesh dialog box opens and an average element size is suggested. We will use the default element size.

✍ The Global Size and Tolerance are given in the preferred units used to create the part.

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2

Click OK. The Mesh Progress window opens and the program starts meshing. After the mesh is completed, you will get the Shell Mesh completed message.

3

Click OK. Notice that a check mark appears on the Mesh icon.


Right-click the Mesh icon and select Show Mesh. The mesh is displayed as shown.

2


3

Right-click the Mesh icon and select Details to display the information about the generated mesh.

Flip misaligned shells Stresses on the top face of a shell element are, in general, different from those on its bottom face. Therefore, it is essential to align faces of adjacent shells properly before running the analysis. After meshing is completed, COSMOS/Works allows you to easily identify top and bottom faces of shell elements. After showing the mesh, top faces will be shown in the shaded color of the model and bottom faces will be shown in the selected Fill Color in the Mesh Preferences dialog box. By visual inspection of the model, you will find that there are two faces that have to be flipped. These faces are shown in the following figure.


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✍ You may get different misaligned shells based on the version or service pack of SolidWorks that you are using. , Flip these shell elements

To flip misaligned shells: 1

In the graphics area, select one of the faces shown in figure.

2

In COSMOS/Works Manager, right-click the Mesh icon and select Flip shell elements. The shell elements will be flipped.

3

Repeat steps 1-2 for the other face.



In the COSMOS/Works Manager tree, right-click the Shell study icon and select Run. Static analysis starts. When the analysis is completed, you will get the Static Analysis completed message.

2

Click OK. COSMOS/Works automatically creates postprocessing folders in the COSMOS/Works Manager tree. For static analysis, the program creates folders for stress, displacement, strain, deformed shape and design check results.

Postprocessing Results of the Static Study First, let us generate the standard plots for static analysis.

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von Mises Stress Plot Von Mises stresses are calculated based on the stress components. They give an overall picture of the stress field. To plot von Mises stresses on the top faces of the model: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Stress icon. The Plot1 icon appears in the Stress folder.

2

Double-click the Plot1 icon. The von Mises stress fringe plot is generated. ✍ The default plots are always generated on the top faces of the shell model.

To change the units of the plot: 1

Right-click the Plot1 icon and select Edit Definition. The Stress Plot dialog box opens.

2


3

Click OK.

✍ By default, the stresses are plotted on the deformed shape. To plot von Mises stresses on the bottom faces of the model: 1

In the COSMOS/Works Manager, right-click the Plot1 icon and select Edit Definition. The Stress Plot dialog box opens.

2


3

In the Plot Type box, select Bottom from the Shell Face drop-down menu.


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4


Accept the rest of the defaults and click OK.


In the COSMOS/Works Manager tree, right-click the Plot1 icon in the Stress folder and select Animate. The Animation dialog box opens.

2

Click the right arrow button

3


4


to start the animation. to stop the animation.

✍ You can save your animation as an AVI movie file by checking the Save As AVI checkbox. Equivalent Element Strain Plot To plot equivalent element strain:

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1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Strain icon. The Plot1 icon appears in the Strain folder.

2

Double-click the Plot1 icon. The equivalent element strain fringe plot is generated.

3

Click the Animate in the COSMOS/Works Manager to animate the plot as was described for the stress plot.

Resultant Displacement Plot To plot the resultant displacement: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Displacement icon. The Plot1 icon appears in the Displacement folder.

2

Double-click the Plot1 icon. The resultant displacement fringe plot is generated.

Deformation Plot To generate the deformed shape plot: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Deformation icon. The Plot1 icon appears in the Deformation folder.

2


Printing and Saving Plots To print a plot: 1

In the COSMOS/Works Manager tree, double-click the desired plot icon.

2

Right-click the desired plot and select Print. The Print dialog box opens.

3

Click OK to print.

To save a plot as VRML or BMP file: 1

In the COSMOS/Works Manager tree, double-click the desired plot.

2

Right-click the desired plot and select Save As. The Save As dialog box opens.

3

From the Save As Type drop-down list, select VRML files (*.wrl), or Bitmap files (*.bmp).

4

Set the location and the name of the file.

5

Click Save.

This lesson is completed. Learning to Use COSMOS/Works

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n Lesson 4: Analysis of an I-Beam (Shell Modeling)

Lesson 4: Analysis of an I-Beam (Shell Modeling) In this lesson, we will create two studies for the I-beam shown below. We will use shell meshing in the first study and solid meshing in the second study.



2

Change the Look in folder to ...\Examples where “...” refers to the folder of the COSMOS/Works installation.

3


4

Double-click the Ibeam.SLDPRT file. ✍ At this point, we recommend that you click File, Save As to save the part with a different name before defining a study so that you can use the original file again. ✍ If you do not see the COSMOS/Works menu, click Tools, Add-ins, check the COSMOS/Works checkbox and click OK.

To start the COSMOS/Works Manager:


Click the COSMOS/Works Manager icon located at the bottom of the FeatureManager window.

Create a Static Analysis Study To create a static analysis study: 1

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On SolidWorks menu, click COSMOS/Works, Study. The Study dialog box opens.

2


3

In the New Study field, type Shell Study as the name of the new study.

4


5

In the Mesh Type box, click the Shell using midsurfaces button. The program displays a message that the shell modeling can be applied to thin parts only. Click OK.

6

Click OK. You will return to the Study dialog box.

7

Click OK.

Assign Material To Assign a Material from the COSMOS/M Library: 1

Right-click the Ibeam icon in the Solids folder and select Apply/Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type drop-down list, select Steel.

3

From the Material Name list box, select Alloy Steel.

4

Click OK. The material is assigned to the part.

Insert Restraints and Loads We will fix one end of the beam and apply normal pressure to the top flange. To fix one end of the beam: 1

Select the face at one end of the beam. The face highlights as shown.

2

Right-click the Load/Restraint folder and select Restraints. The Restraints dialog box opens.

Select this face

✍ In the Selected Entities box, notice that one face is selected. 3

From the Type box, click Fixed.

4

Click OK


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To apply uniform pressure to the flange: 1

Select the top face of the top flange. The face highlights as shown.

2

Right-click Load/Restraint folder and select Pressure. The Pressure dialog box opens.

Select this face

✍ In the Selected Entities list box, notice that one face is selected. 3

In the Type box, click Along plane Dir 2 (direction 2 of Plane 1).

4


5

From the Units drop-down list, verify that SI is selected.

6

In the Value field, enter -1000.

7


8

Right-click the Load/Restraint folder again and choose Hide All to hide load and restraint symbols.

Mesh the Part To set mesh preferences:

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1


2


3


4


5

From the Jacobian Check drop-down menu, select 4 Points.

6

Click OK.

To mesh the part: 1

Right-click the Mesh icon and select Create. The Mesh dialog box.

2

Drag the slider to the most right position on the scale as shown. ✍ The type of mesh (shell or solid) was specified when the study was created. The Global Size and Tolerance are given in the preferred units used to create the part.

3

Click OK. Meshing starts.

4

After the meshing is completed, you will get the Shell Mesh completed message. Click OK. Notice the checkmark that appears on the Mesh icon in the COSMOS/Works Manager tree.

To view the mesh: 1

Right-click the Mesh icon and select Show Mesh.

2

Right-click the Mesh icon again and click Hide Mesh to hide the mesh.

3

Right-click on Mesh icon and choose Details to display meshing information.



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Running Static Analysis To run static analysis: 1

Right-click the Shell Study icon and select Run. Analysis starts. When the analysis is completed, you will get the Static Analysis completed message.

2

Click OK. COSMOS/Works automatically creates result folders in the COSMOS/Works Manager tree under the Shell study icon.

Postprocessing Results of the Shell Study To plot von Mises stresses on the top faces of the model: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Stress icon. The Plot1 icon appears in the Stress folder.

2


✍ The default plots are always generated on the top faces of shell models. ✍ By default, the stresses are plotted on the deformed shape. To plot von Mises stresses on the bottom faces of the model:

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1

In the COSMOS/Works Manager, right-click the Plot1 icon in the Stress folder and select Edit Definition. The Stress Plot dialog box opens.

2


3


4

Click OK.


Right-click the Plot1 icon in the Stress folder and select Animate. The Animate dialog box opens.

2

Click the right arrow button to start the animation.

3

Click the square button to stop the animation.

4


To plot the equivalent element strain: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Strain icon. The plot1 icon appears in the Strain folder.

2



In the COSMOS/Works Manager tree, click the (+) sign to the left of the Displacement icon. The Plot1 icon appears in the Displacement folder.

2



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Verify the Results with Solid Mesh Create a Solid Mesh Study To create a solid mesh static analysis study: 1

From the COSMOS/Works menu, click Study. The Study dialog box opens.

2


3

In the New Study field, type Solid Study (or any other name) as the name of the new study.

4


5

From the Mesh Type box, click the Solid button.

6


7

Click OK.

Assign Material and Apply Loads/Restraints You can apply material and restraints exactly as described for the Shell study. Instead, we will use drag and drop to define the new study. To assign material: 1

Right-click the Solids icon in Shell Study folder and select Copy.

2

Right-click the Solids Study folder and select Paste. The material will be copied. - or Drag the Solids icon from the Shell Study and drop it on the Solid Study folder. The material is copied.

To apply loads/restraints: 1

Right-click the Load/Restraint folder in the Shell Study folder and select Copy.

2

Right-click the Solid Study folder and select Paste. The loads and restraints will be copied. - or Drag the Load/Restraint folder from the Shell Study and drop it on the Solid Study. The restraints are copied.

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Mesh the Part We will the use same mesh preferences as those we used in the shell example. To mesh the part: 1


2

Click OK to accept the default element size.

To show/hide the mesh:

1

Right-click the Mesh icon and select Show Mesh. The mesh is displayed.

2


3

Right-click the Mesh icon and select Details to display the information about the mesh.



Right-click the Solid Study icon and select Run. Analysis starts. When the analysis is completed, you will get the Static Analysis completed message.

2

Click OK.


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Postprocessing Results of the Solid Study Von Mises Stress Plot To plot von Mises stresses: 1

Click the (+) sign to the left of the Stress icon in the Solid study. The Plot1 icon appears in the stress folder.

2

Double-click Plot1. The von Mises stress fringe plot is generated.

To plot the equivalent element strains:

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1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Strain folder in the Solid study.

2

Double-click Plot1.

Resultant Displacement Plot To plot the resultant displacements: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Displacement icon.

2




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n Lesson 5: Analysis of a Funnel (Shell Model)

Lesson 5: Analysis of a Funnel (Shell Model) In this lesson, you will learn:

q q q

Applying local boundary conditions Applying non-zero prescribed displacements Shell meshing


Start SolidWorks. The initial window of SolidWorks opens.

2

From the File menu, click Open. The Open dialog box opens.

3

Browse to the folder in which you installed COSMOS/Works.

4

Click the Examples folder.

5

Choose the funnel.prt file.

6

Click Open. The part file opens.

7

Verify that COSMOS/Works appears in the top menu bar of SolidWorks. ✍ If you do not see the COSMOS/Works menu, choose Tools, Add-ins, click the control box for COSMOS/Works and click OK.

To check the units: 1

Click Tools, Options.

2


3

Make sure that Millimeters appears in the Linear units field.

4

Click OK. ✍ At this point, it is recommended that you click File, Save As to save the part with a different name before defining a study so that you can use the original file again.

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To start the COSMOS/Works Manager:


Click the COSMOS/Works Manager button located at the lower left corner of the SolidWorks window.

Create a Static Analysis Study To create a static analysis study: 1

From the COSMOS/Works menu, click Study. The Study dialog box opens.

2


3

In the New Study field, type Shell Study (or any other name) as the name of the new study.

4


5

From the Mesh Type box, click Shell using midsurfaces. A message window opens.

6

Read the message and click OK.

7


8


9

Click OK.

Assign Material To assign a material from the COSMOS/M Library: 1

Right-click the funnel icon in the Solids folder and select Apply/Edit. The Material dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type drop-down list, select Plastics.

3

From the Material Name list box, select Nylon 6/10.

4

From the Unit System drop-down list, click the desired system of units to use it in displaying the properties.

5

From the Property Type drop-down list, choose All.

6

Click OK.


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Insert Loads and Restraints A rigid cylindrical boss of a 121 mm radius is to fit in the cylindrical base of the funnel. As the inner radius of the base is 120 mm, this condition may be simulated by prescribing a 1 mm displacement in the radial direction. To prescribe radial translation: 1

Select the inner face of the cylindrical base. The face highlights as shown.

2


Select this face

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3

In the Selected Entities list box, notice that one face is selected.

4

From the Type box, click On Cylindrical Face.

5

From the Displacement Units drop-down list select mm.

6

Click the checkbox associated with Radial Displacement. A checkmark appears.

7

Type in 1.0 in the Radial Displacement field.

8

Click OK.

To fix the bottom face in the axial direction: Select Axis1 from SolidWorks

1

Change the view as shown and select the bottom face of the funnel.

2

Click the FeatureManager button at the lower left corner of the SolidWorks window to switch to the FeatureManager tree.

3

Press and hold down Ctrl and click Axis1 in the FeatureManager tree.

4

Click the COSMOS/Works Manager button to switch back to the COSMOS/Works Manager tree.

FeatureManager

Select this face

5


6

In the Selected Entities list box, notice that one face is selected.

7

In the Type box, verify that Use Reference plane or Axis is selected.

8

In the Selected References list box, verify that Axis1 is selected.

9

Click the checkbox of Axial Displacement and verify that 0 is entered in its field.

10

Click OK. The restraint is applied so that this face may not move in the axial direction.


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To make the top face immovable:

Select this face

1

Change the view as shown and select the top face of the funnel.

2


3

From the Selected Entities list box, notice that one face is selected.

4

In the Type box, click Immovable (No Translation).

5

Click OK. The restraint is applied so that this face cannot move in any direction. ✍ Immovable and Fixed are different for shells. Fixed sets all translations and Rotations to zero while Immovable sets only the translations to zero.

6

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Right-click the Load/Restraint folder in the COSMOS/Works Manager tree and choose Hide All to hide the restraint symbols.

COSMOS/Works User’s Guide

Mesh the Part To set mesh preferences: 1


2


3

In the Mesh Control, select Smooth Surface.

4


5


6

Click OK.

To mesh the part: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and select Create.

2

Accept the default element size and click OK. The Mesh Progress window opens and the program starts meshing.

3

When the mesh is completed, you will get the Shell Mesh completed message. Click OK to close the dialog box.

To show/hide the mesh: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and select Show Mesh. The mesh is displayed.

2



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3

Right-click the Mesh icon and select Details to display information about the generated mesh.

Flip this face

Before flipping

After flipping

Flip misaligned shells Stresses on the top face of a shell element are, in general, different from those on its bottom face. Therefore, it is essential to align faces of adjacent shells properly before running the analysis. After meshing is completed, COSMOS/Works allows you to easily identify top and bottom faces of shell elements. After showing the mesh, top faces will be shown in the shaded color of the model and bottom faces will be shown in the selected Fill Color in the Mesh Preferences dialog box. By visual inspection of the model, you will find that there is one face that has to be flipped. This face is shown in the above figure. ✍ You may get different misaligned shells based on the version or service pack of SolidWorks that you are using. To flip misaligned shells: 1

In the graphics area, select the face shown in figure.

2

In COSMOS/Works Manager, right-click the Mesh icon and select Flip shell elements. The shell elements will be flipped.


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Right-click the Shell Study icon and select Run. Analysis starts. When the analysis is completed, you will get the Static Analysis completed message.

2

Click OK.

Visualizing the Results To plot von Mises stresses on the top faces of the model: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Stress folder. The Plot1 icon appears in the Stress folder.

2

Double-click Plot1. The stresses on the top face are plotted.

Global Coordinate System

✍ The default plots are displayed on the top faces of the model. To plot von Mises stress on the bottom faces of the model: 1

Right-click the Plot1 icon in the Stress folder and select Edit Definition. The Stress Plot dialog box opens.

2


3



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4


Click OK.

✍ To visualize extreme stresses, we recommend that you plot the stresses on top and bottom faces for all shell models. To change the display settings of the result axes: 1

Activate Plot1 by double-clicking its icon.

2

Right-click Plot1 and select Axes. The Axes dialog box opens.

3

In the Axis box, move the size sliders to the positions shown in figure.

4

In the Ticks fields, enter 6.

5

In the Grid box, check XY, YZ, and ZX checkboxes.

6

Click OK.

Global coordinate system displayed with the settings shown in the Axes dialog box shown to the left

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To change the stress units: 1

In the COSMOS/Works Manager tree, right-click the Plot1 icon in the Stress folder and select Edit Definition. The Stress Plot dialog box opens with the Properties tab selected.

2

From the Stress Units menu, select the desired unit and click OK. The plot with new units will be displayed.


Right-click the Plot1 icon in the Stress folder and select Animate. The Animation dialog box opens.

2


3


4



✍ You can save your animation as an AVI movie file by checking the Save As AVI checkbox. Equivalent Element Strain Plot To plot the equivalent element strains: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Strain icon. The Plot1 icon appears in the Strain folder.

2



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In the COSMOS/Works Manager tree, click the (+) sign to the left of the Displacement icon. The Plot1 icon appears in the Displacement icon.

2



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Lesson 6: Analysis of a Fuel Storage Tank (Shell Model) In this lesson, you will learn how to:

q q q q

Create a coordinate system, Apply variable pressure, Run static analysis, and Visualize stress and displacement results. Fuel

Density of Fuel is 0.029 lb/in3.

y

p(y) =γy

Description An aluminum storage tank is partially filled with a fuel of density γ = 0.029 lb/in3. The fuel exerts a hydrostatic pressure that can be simulated by applying a varying pressure. A linearly varying pressure (p(y) =γy) will be applied to all inner faces of the tank below the fuel surface, where y refers to the vertical distance measured from the surface of the fuel. In order to apply the pressure p(y) =γy, the faces of the tank were split at the surface of the fluid so that we can apply the pressure to the walls of the tank below the surface of the fluid. We will also create a coordinate system at the fluid surface with its y axis pointing downwards in order to be able to describe the pressure variation in the y direction according to the above equation.


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n Lesson 6: Analysis of a Fuel Storage Tank (Shell Model)

Open the Model and Create a Static Study Open the Fuel_Storage_Tank part located in the Examples folder of the COSMOS/Works installation. ✍ We recommend that you click File, Save As to save the part to a different name before defining a study so that you can use the original file again. To create static analysis study: 1

Right-click the Fuel_Storage_Tank part icon and select Study.

2

In the Study dialog box, click the Add button. The Study Name dialog box opens.

3

In the New Study field, enter variable pressure as the name of the study.

4

From the Analysis Type menu, make sure that Static is selected.

5

In the Mesh Type box, select Shell using midsurfaces. You will be prompted with a message that the shell meshing works only for simple thin parts and is being improved by both SRAC and SolidWorks. Close this information window by clicking OK.

6


7

Click OK to close the Study dialog box. ✍ In the variable pressure study we will use the first shell meshing technique, namely, Shell using midsurfaces. In order for this technique to work, SolidWorks 2000 with SP3 service pack or higher should be installed on your computer.

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Assign Material to the Model Assign Aluminum Alloy (1060 Alloy) from the COSMOS/M Material Library to the tank.

Apply Restraints and Pressure to the Model Apply displacement restraints to the bottom faces of the tank To restrain the bottom face of the tank: 1

Select the bottom faces of the tank (3 faces).

2

In the COSMOS/Works Manager, right-click the Load/Restraint icon and select Restraints .

3

In the Type box, select Immovable.

4

Click OK.

Apply the hydrostatic pressure First, we will create a coordinate system at the surface of the fuel with its y- axis pointing downward.

Fix these faces

To create a coordinate system at the surface of the fuel: 1

In SolidWorks menu bar, click Insert, Reference Geometry, Coordinate System. The Coordinate System dialog box opens.

2

Click inside the Origin box and select the vertex shown in the figure.

3

Click inside the Y Axis box, and select the edge shown in the figure.

4

Click OK. The coordinate system will be created and highlighted.


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Select this edge as the Y-axis

Select this vertex as the origin

To apply hydrostatic pressure to the inner faces of the tank: 1

Select the coordinate system you just created, hold the Ctrl key down and select all inner faces that are below the fluid surface in the tank (total of 7 faces).

2

In the COSMOS/Works Manager, right-click the Load/Restraint icon and select Pressure. The Pressure dialog box opens.

3

In the Type box, select Normal to selected face.

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4

In the Distribution box, make sure that Variable is selected.

5


6

In the Value field, enter 1.0.

7

In the Selected Coord. System box, make sure that Coordinate System1 is selected.

8

In the Equation for Variable Pressure fields, enter 0.029 in the field corresponding to the y coefficient and 0 in all other fields.

9

Click OK.

Mesh the Model To mesh the part: 1

Right-click the Mesh icon and select Preferences. Use the options shown in figure below.

2

Right-click the Mesh icon again and select Create.

3

Click OK to accept the default element size and tolerance.

To show the mesh: Right-click the Mesh icon and click Show Mesh. The mesh will be displayed. Flip misaligned shells Stresses on the top face of a shell element are, in general, different from those on its bottom face. Therefore, it is essential to align faces of adjacent shells properly before running the analysis. After meshing is completed, COSMOS/Works allows you to easily identify top and bottom faces of shell elements. After showing the mesh, top faces will be shown in the shaded color of the model and bottom faces will be shown in the selected Fill Color in the Mesh Preferences dialog box. By visual inspection of the model, you will find that there are two faces that have to be flipped. These faces are shown in the figure below. ✍ You may get different misaligned shells based on the version or service pack of SolidWorks that you are using.


2-75



To flip misaligned shell elements: 1

Select one of the misaligned faces.

Right-click the Mesh icon and select Flip shell elements. 3 Select the other face and repeat steps 1-2. 2

Before Flipping

Select these faces and flip the associated elements

Run the Analysis Right-click the study icon and select Run.

Visualize Stress and Displacement Results To plot von Mises stress on the top faces of the model: 1

In the COSMOS/Works Manager, click the (+) sign to the left of the Stress folder.

2

Double-click the Plot1 icon. ✍ The default plots are always displayed on the top faces of the model.

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After Flipping

To plot von Mises stress on the bottom faces of the model: 1

Right-click the Plot1 icon in the Stress folder and select Edit Definition. The Stress Plot dialog box opens.

2


3


4

Click OK.

To plot displacement results: 1

In the COSMOS/Works Manager, click the (+) sign to the left of the Displacement folder.

2

Right-click the Plot1 icon in the Displacement folder and select Edit Definition. The Displacement Plot dialog box opens.

3

On the Properties tab, select in (inch) from the Displacement Units drop-down menu.

4

Click OK.



2-77

Lesson 7: Analysis of a Pulley Under a Bearing Force In this lesson, you will learn how to:

q

Create a coordinate system, and

q

Apply forces with prescribed intensity. f(θ) = F0Sin(θ) = (F0)(y/a)

X

θ

a

Y

f(θ) = F0Sin(θ) = (F0)(y/a) where f(θ) is the intensity of the force, a is the radius of the hole, and F0 is a scale factor calculated by the program such that the sum of all forces is set equal to the specified force value.

Description COSMOS/Works lets you handle bearing problems in two ways: • You can model the assembly of the axle and the pulley. The forces are transferred through the gap elements generated automatically by setting the Contact/Gaps option on the faces of contact between the axle and the pulley. • You can model the pulley only and approximate the force intensity exerted by the axle. The validity of the approximation depends on the validity of the assumed force intensity for the problem at hand. The second approach is used in this lessons force exerted by the axle on the pulley is approximated by a 700 pound force acting normal to the lower face of the hole. The intensity is assumed to be f(θ) = Sin(θ), where θ is defined as shown in the figure.

2-78


The surface of central hole of the pulley was split into two faces. We will create a coordinate system at the center of the hole as shown in the figure and use it to specify a total normal force with given intensity.

Open the Model and Assign Material 1

Open the Pulley-Bearing part located in the Examples folder of the COSMOS/ Works installation folder.

✍ We recommend that you click File, Save As to save the part to a different name before defining a study so that you can use the original file again. 2

Start the COSMOS/Works Manager.

3

Create a Static analysis study. Make sure to select the Solid option while defining the study.

4

Assign Steel Alloy from the COSMOS/M Material Library to the pulley.

Apply Restraints and Force to the Model Apply displacement restraints To restrain a portion of the lower face of the rim: 1

Select the face shown in the figure.

2

In the COSMOS/Works Manager, rightclick the Load/Restraint icon and select Restraints.

3


4

Click OK.

Select this face to apply restraints


2-79


n Lesson 7: Analysis of a Pulley Under a Bearing Force

Apply the bearing force First, we will create a coordinate system at the center of the pulley. To create a coordinate system at the center of the pulley: 1

In SolidWorks menu bar, click Insert, Reference Geometry, Coordinate System . The Coordinate System dialog

box opens and a default coordinate system is created. 2

Flip the y-axis by clicking the Flip checkbox under Y Axis.

3

Click OK.

To apply the bearing force:

2-80

1

With the newly created coordinate system selected from the previous procedure, hold the Ctrl key down and select the lower half of the surface of the central hole.

2

In the COSMOS/Works Manager, right-click the Load/Restraint icon and select Force. The Force dialog box opens.

3

In the Type box, select Apply Normal Force .

4

In the Distribution box, make sure that Variable is selected.

5


6

In the Force field, enter 700.

Create a local coordinate system to define variable force

7In

the Selected Coord. System box, make sure that Coordinate System1 is selected.

8In

the Equation for Variable Force fields, enter

1.3333 in the field corresponding to the y coefficient and 0 in all other fields. 1.333. is the

coefficient of y in the force intensity equation: f(y) = (1/a)y = (1/0.75)y= 1.333 y. where a is the radius of the cylindrical hole. 9

Click OK.

✍ The summation of the magnitudes of the forces applied normal to the face will be 700 pound force. The horizontal components over the face will cancel each other.

Mesh the Model To mesh the part: 1

Right-click the Mesh icon and select Preferences. Use the options shown in figure.

2

Right-click the Mesh icon again and select Create.

3

Click OK to accept the default element size and tolerance.

Run the Analysis Right-click the study icon and select Run.


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Visualize Stress and Displacement Results To plot von Mises stress:

1

In the COSMOS/Works Manager, click the (+) sign to the left of the Stress folder.

2

Right-click the Plot1 icon and select Edit Definition.

3

Click the Setting tab.

4

Change the Scale Factor to 2000.

5

Click OK.

To plot displacement results:

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1

In the COSMOS/Works Manager, click the (+) sign to the left of the Displacement folder.

2


3

Click the Setting tab.

4

Change the Scale Factor to 2000.

5

Click OK.

To list the reaction forces: 1

Select the restrained portion of the lower face of the rim.

2

Right-click the Displacement folder and select Reaction Force . The Reaction Force dialog box opens to list the reaction forces on the selected face as well as on the entire model.

3

From the Units menu select lb. Y

X

Global coordinate system of the problem


2-83



Explanation of reaction forces The following graph shows the forces that developed on the contact area between the pulley and the axle, Fn(θ)=Fosin(θ) is the normal force applied at an angle (θ)

Fo X

Y

θ Fn

Fosin(θ)cos(θ)

Fosin(θ) Fosin (θ) 2

The program calculates Fo such that the summation of the magnitudes of all applied forces is set equal to the specified force value (700 lb)

According to the above graph, The summation of the magnitudes of the normal forces =700 lb The summation of the magnitudes of the horizontal forces=700- 541.17= 158.83lb The summation of the magnitudes of the vertical forces= Reaction forces on the entire model= 541.17 lbs ✍ The applied net horizontal force is zero. This lesson is completed.

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Lesson 8: Stress Concentration Around a Hole in a Plate In this lesson, you will learn how to:

q q

use the p-adaptive method to improve the solution, and visualize convergence graphs related to the p-adaptive method.

Description In this problem, we will study the stress concentration around a hole at the center of a plate subjected to in-plane pressure loading. 20”

20” 1” radius

10”

The plate is 20” x 20” x 1” and the radius of the hole is 1”. Due to the symmetry of the model, we will analyze a quarter of the plate as shown in the figure. The face of the plate is subjected to a normal uniform tensile pressure of 1000 psi. The hole will cause a stress concentration.

10”

1 in


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n Lesson 8: Stress Concentration Around a Hole in a Plate

Open the Model and Create a Study 1

Open the Plate-with-hole part located in the Examples folder of the COSMOS/ Works installation folder.

✍ We recommend that you click File, Save As to save the part to a different name before defining a study so that you can use the original file again. 2

In the COSMOS/Works Manager, right-click the top icon and select Study.

3

Click the Add tab, enter a name for the study, select Static from the Analysis Type menu (default), make sure to select Solid (default) in the Mesh Type box, and click OK. ✍ The p-adaptive method is not supported for shells.

4

Click the Properties button and then click the Adaptive tab.

5

Click the Use p-Additive for solution checkbox.

6

From the Stop when drop-down menu, select Total Strain Energy (default) and enter 0.02 in the change is % or less field. ✍ In general, strain energy has a rapid convergence. This is why we entered a small value for the allowable change in the strain energy.

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7

In the Update elements with strain energy error of % or more, enter 1.0.

8

In the Starting p-order field, enter 2 (default).

9

Click OK to accept all other defaults.

10

Click OK.

Assign Material To assign Material to the part: 1

Right-click the Solids folder and select Apply Material to All.

2

Click the COSMOS/M Library tab.

3

Click OK to apply Alloy Steel to the part.

Apply Loads and Boundary Conditions To apply the symmetry restraints: 1

Select face A (as shown in the figure).

2

Right-click the Load/Restraint folder, select Restraints.

3

In the Type box, choose the Use Reference Plane or Axis option. Plane1 appears in the selected Reference field.

Restrain this edge normal to Plane1 Face B: Restrain this face in direction 1 of Plane1

Face A: Restrain this face in direction 2 of Plane1

4

Click the Along Plane Dir 1 checkbox and enter 0 in its field.

5

Click OK.

6

Repeat the above steps for face B (as shown in the figure) to restrain it in direction 2 of Plane1.

To stabilize the plate in the direction normal to Plane1: 1

Select the upper edge (as shown in the figure) of the plate.

2

Right-click the Load/Restraint folder and select Restraints.

3

In the Type box, select the Use Reference Plane or Axis , Plane1 appears in the selected Reference field.

4

Click the Normal to plane checkbox and enter 0 in its field.


2-87


5


Click OK.

To apply the tensile pressure: 1

Select the face shown in the figure.

2

Right-click the Load/Restraint folder and select Pressure.

3

In the Type box, select the Along Plane Dir 1 option.

4

In the Distribution box, choose Uniform, English (IPS) units.

5

In the Value field, enter 1000 (psi).

6

Click OK.

1000 psi Pressure

Mesh the Plate To set mesh preference: 1

Right-click the Mesh icon and select Preferences.

2

Select the options shown in the figure.

3

Click OK. ✍ It is recommended to choose the At Nodes option from the Jacobian Check drop-down menu when using the p-method.

2-88

To mesh the plate: 1


2

In the Global Size field, enter 2.0. This is an intentionally large value to show the power of the p-method.

3

Click OK. Click OK when meshing is completed. To show the mesh, right-click the Mesh icon and select Show Mesh.

Run Static Analysis Right-click the icon of the study and select Run to start static analysis. The pmethod will run static analysis 3 loops before reaching convergence. Click OK when the analysis is completed.

Visualize the Results To plot the normal stress in the X-direction: 1

In the COSMOS/Works Manager, right-click the Stress folder and select Define.

2

Click the Display tab and select the SX: Normal stress (X-dir.) component.

3

Click OK.


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To graph the % Change in Global Criterion: 1

In the COSMOS/Works Manager, right-click the study folder icon and select Convergence Graph.

2

Click OK.

To graph Total Strain Energy: 1

Right-click the study folder icon again and select Convergence Graph.

2

Click the checkbox for % Change in Global Criterion to

uncheck it.

2-90

3

Click the checkbox for Total Strain Energy.

4

Click OK.

To graph all convergence components: 1

In the COSMOS/Works Manager, right-click the study folder icon and select Convergence Graph.

2

Check all the available checkboxes.

✍ When you plot more than one graph, the y-axis will be normalized to unity. 3

Click OK.

Verify the Results Maximum Normal Stress Results (SX):

Maximum Normal Stress Sx

Analytical Solution

Using the p-method

3024 psi

3059 psi (1.16% error)

Without using the p-method (same mesh)

2539.5 psi (16% error) (obtained by deactivating the pmethod and re-running the analysis)

Reference Roark and Young, “Formulas for Stress and Strains,” Fifth Edition, McGraw-Hill Book Company, Chapter 15, pp-594.



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3 Contact Stress Analysis Tutorial

This chapter presents step-by-step lessons to show you how to use the Contact/ Gaps Options.

q q q

Lesson 9: Analysis of a Rotating Shaft Assembly Lesson 10: Analysis of an Eyebar Assembly Lesson 11: Analysis of Two Contacting Cantilevers with Rough Surfaces


3-1

Chapter 3 Contact Stress Analysis Tutorial

n Lesson 9: Analysis of a Rotating Shaft Assembly

Lesson 9: Analysis of a Rotating Shaft Assembly In this lesson, you will learn how to:

q q q q

Set a global Contact/Gaps option, Mesh an assembly, Run static analysis, and Visualize the stress results.

Description The imbalance in the motor causes a dynamic force of 5 pounds on the rotating shaft. The worst scenario occurs when the shaft rotates at a frequency that is equal to one of the natural frequencies of the assembly (resonance). Assuming a damping ratio (ξ) of 5%, the dynamic force effect may be approximated by applying a static force of magnitude 1/(2ξ) times the magnitude of the dynamic force. We will, however, use a static force of 150 pounds (50 pounds times a factor of safety of 3) to evaluate the stresses caused by the imbalance at the interface between the shaft and bearings. Note that the direction of the imbalance changes as the shaft rotates. In this example, we will consider a force in the upward direction.

Retrieve the Part To retrieve the part:

3-2

1

Start SolidWorks.

2

From the File menu, select Open. The Open dialog box opens.

3


4

Click the Examples\Contact folder.

5

From the Files of type menu, select Assembly Files (*.asm;*.sldasm).

6

Choose the Contact-Ex-1 assembly file in the Contact folder.

7

Click Open. The assembly opens.

8

Verify that COSMOS/Works appears in the top menu bar of SolidWorks.

✍ If you do not see the COSMOS/Works menu, click Tools, Add-Ins, select COSMOS/Works and click OK. ✍ Lightweight components do not function properly with COSMOS/Works. To turn off the automatic loading of components as lightweight, turn off the option with Tools, Options, Performance. ✍ It is recommended that you click File, Save As to save the assembly with a different name before defining a study so that you or can use the original file again.


3-3



Create a Static Analysis Study ✍ The Contact/Gaps capability works with static analysis only, it does not work with frequency, buckling, or thermal analysis. To start the COSMOS/Works Manager: Click the COSMOS/Works Manager tab SolidWorks window.

located at the lower left corner of

✍ To return to the FeatureManager design tree, click the FeatureManager tab. . To create a static analysis study: 1

Right-click the Contact-Ex-1 assembly icon and click Study. The Study dialog box opens.

2


3

In the New Study field, type in Imbalance.

4

From the Analysis Type dropdown menu, choose Static (default).

5

From the Mesh Type box, choose Solid.

6


7

Click the Properties button. The Static analysis setting box opens. ✍ You can use either the Direct Sparse or the FFEPlus solver for static problems involving contact.

3-4

8

In the Solver box, check FFEPlus.

9

Click the OK button. You will return to the Study dialog box.

10

Click the OK button. The study is created.

Preprocessing Assign Material To assign material from the COSMOS/M Library: 1

In the COSMOS/Works Manager tree, right-click the Solids folder icon and click Apply Material to All. The Material dialog box opens with the COSMOS/M Library tab selected.

2

Click the OK button to assign the default Alloy Steel to all parts in the assembly.

✍ Notice the checkmarks that appear on the icons in the Solids folder indicating that a material has been assigned to each of them. Insert Loads and Boundary Conditions The imbalance in the motor-shaft assembly is estimated to cause a static force of 50 pounds. Since we want to perform static analysis, we will use a factor of safety of 3 and apply 150 pounds. The force can be in any direction, however, in this study, we apply the force in the vertical direction pointing upward. To insert restraints: 1

Select the bottom faces of the bearing supports as shown (select one face, press and hold down the Ctrl key and select the other one). The two faces should highlight as shown in the figure.

2

In the COSMOS/Works Manager tree, right-click the Load/Restraint icon and click Restraints. The Restraints dialog box opens.

✍ Notice that the Selected Entities box lists the number of selected faces, edges or vertices. In this case, two faces are selected. 3

From the Type box, choose Immovable.

4

Click the OK button. Restraints are applied to the selected faces and displayed in the selected color.


3-5



To apply a uniform upward force: 1

Click the FeatureManager tab and select Plane2 located at the bottom of the FeatureManager design tree. Plane2 highlights in the graphics area.

2

With Plane2 selected from step 1, click the COSMOS/Works Manager tab

3

Press and hold the Ctrl key and select the lower face of the shaft connected to the motor. The face highlights.

4

In the COSMOS/Works Manager tree, right-click the Load/Restraint icon and select Force. The Force dialog box opens.

select Plane2

select the lower face of the shaft

5

In the Type box, click Apply Force/Moment.

6


7


8

In the Force box, check Normal to plane checkbox and enter -150 in its field. ✍ Note that when you check the Normal to plane checkbox, Plane2 will appear in the Selected Reference field.

9

3-6

Click OK. The force is applied.

force symbols on the lower face of the shaft

.

Mesh the Assembly To consider contact in the analysis, you have to set its options before meshing the model. You can specify global contact conditions that apply to all contacting faces, and in addition, you can specify contact conditions to selected pairs of faces. For more information about available contact options in COSMOS/Works, please refer to Meshing Your Model chapter in the User’s Guide. In this lesson we will set the default global contact option. To set a contact condition: 1

In the COSMOS/Works Manager, right-click the Contact\Gaps icon. A right-mouse menu opens.

2

Make sure that Touching Faces: Node to Node option is checked. ✍ If you want to change the contact condition later on, you have to remesh the model in order for this change to take effect in the analysis.

To set the meshing preferences: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and click Preferences. The Preferences dialog box opens with the Mesh tab selected.

2


3


4

In the Mesher Type, select Standard.

5


6

Click OK.

To mesh the part: 1

In the COSMOS/Works Manager tree, right-click the Mesh icon and click Create. The Mesh dialog box opens.

2

In the Global Size field, type in 0.5 (inches). The Tolerance will automatically change to 5% of the Global Size (0.025).

3

Click OK. The Mesh Progress window opens and the program starts meshing the model.


3-7



To view the mesh: 1

In the COSMOS/Works Manager, right-click the Mesh icon and select Show Mesh. The mesh is displayed.

2

Right-click the Mesh icon and select Hide Mesh .

3

Right-click the Mesh icon and select Details to display information about the mesh.

Run Static Analysis As noted earlier when defining the properties of the study, contact analysis works with either the Direct Sparse or the FFEPlus solver. Right-click the Imbalance icon in the COSMOS/Works Manager tree and select Details to verify this requirement. To run static analysis: 1

In the COSMOS/Works Manager tree, right-click the Imbalance study icon and click Run. Analysis starts. When the analysis is completed, you will get the Static Analysis Completed message.

2

Click OK.

Visualizing Static Results von Mises Stress Plot Von Mises stress is calculated from stress components in various directions. It gives an overall picture for the stress field on the model. To plot von Mises stress field: 1

3-8

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Stress icon. The Plot1 icon appears under the Stress icon.

2

Double-click the Plot1 icon. Von Mises stresses are plotted as shown.

✍ By default, the stresses are plotted on the deformed shape. To animate the stress plot: 1

In the COSMOS/Works Manager tree, right-click the Plot1 icon under the Stress tree and click Animate. The Animation dialog box opens.

2


3


4


to start the animation. to stop.

✍ You can save your animation as an AVI movie file by checking the Save As AVI control box.


3-9



To plot von Mises stresses on the true deformed shape: 1

Right-click the Plot1 icon and choose Edit Definition.

2

Click the Settings tab.

3

Change the scale to 1.0.

4

Click OK.

5

Click View, Orientation, and double-click *Front.

6

Click the Pin all times.

to have the Orientation box available at

✍ Notice that due to the applied upward force, stresses have developed at the upper contact of the shaft with the bearing due to compression. ✍ No stress concentration appears at the lower connection since a gap will develop at the front end as will be illustrated by a section plot.

3-10

Section Plot To generate a section plot of von Mises stress: 1

In the COSMOS/Works Manager tree, right-click the Stress folder and click Define. The Stress Plot dialog box opens.

2

On the Properties tab, select psi from the Stress Units drop-down menu.

3


4


5

From the Fringe Type menu select Filled, Discrete.

6

Click the Settings tab.

7

In the Boundary Options list box select None.

8

In the Scale Factor field, enter 2000.

9

Click OK.

10

To change the orientation of the model, double-click Isometric in the Orientation box.

Using the Clipping tool with the section plot: 1


2

Right-click the Plot2 icon in the COSMOS/Works Manager and click Clipping. The Section Clipping setting box opens.

3

In the Cut Direction menu, choose Both.

4

Click OK to close the Section Clipping dialog box.

5

Double-click *Right in the Orientation box. The following plot is generated.


3-11


6


Zoom-in to the stress concentration area, the circles show the contact areas where compressive stresses develop. The rectangles show the areas where they separate from each other and gaps develop between them.

✍ You can create other studies by applying forces in other directions.


3-12

Lesson 10: Analysis of an Eyebar Assembly In this lesson, you will learn how to:

q q q q

Define global and local contact conditions. Use the symmetrical restraint condition. Run static analysis, and Visualize the stress results. Fixed Tensile Pressure

Description The Eyebar assembly is loaded and supported as shown. We will use a global Node to Node contact condition on contacting faces to evaluate stress concentrations. Due to symmetry, we will analyze one quarter of the model with the appropriate boundary conditions. Since most of the steps are identical to the first example in this chapter, we will describe them briefly. Plane of symmetry

Plane of symmetry No motion normal to the two planes of symmetry.


3-13


n Lesson 10: Analysis of an Eyebar Assembly

Open the Model, Assign Material, and Apply Loads/Restraints 1

Open the QuarterEyeBar assembly located in the Examples\Contact folder of the COSMOS/Works installation directory.

✍ If you do not see the COSMOS/Works menu, click Tools, Add-Ins, select COSMOS/Works and click OK. ✍ We recommend that you click File, Save As to save the assembly with a different name before defining a study so that you can use the original file again.

3-14

2

Start COSMOS/Works Manager.

3

Create a Static analysis study. Make sure to modify the properties of the study to use the FFEPlus solver.

No normal motion

4

Assign the default Alloy Steel from the COSMOS/M Material Library to both parts.

5

Constrain the 5 flat faces coinciding with the two planes of symmetry in the normal direction.

6

Apply the Immovable restraint to the end of the bolt.

7

Apply a tensile pressure of -300 psi to the end face of the eyebar part as shown in the figure.

Immovable Face

300 psi

Mesh the Model Before we proceed with the meshing of the model, we need first to specify a contact condition at the contacting surfaces. We will define a global contact condition between the common surfaces of the bolt and the eyebar as Node to Node contact type. To define a global contact condition: In the COSMOS/Works Manager, right-click the Contact/Gaps icon and check Touching Faces: Node to Node.

✍ In order for the specified contact condition to be considered when running the analysis, you should specify the contact condition before meshing the model. To mesh the assembly: 1

Right-click the Mesh icon and select Preferences. Use the options shown in the figure.

2



3-15


3

n Lesson 10: Analysis of an Eyebar Assembly

Accept the default element size and click OK.

To run the analysis: Right-click the study icon and select Run. To Visualize Stress results: 1

Click the (+) sign to the left of the Stress folder.

2


3

On the Properties tab, select psi from the Stress Units drop-down menu.

4

Click the Display tab and select P1: Normal stress (1 st principal).

5

Click OK.

6

To change the view of the model, click the Front tool

.

Defining Alternative Contact Condition Instead of choosing a global Touching Faces: Node to Node contact condition on the contacting faces of the model, we could have defined, in addition to the global option, a local Free contact condition between the two faces shown in the figure. By making such choice, we implicitly assume that the selected faces will separate upon applying the pressure. The advantage of making such choice is that less computing time is needed to solve such problem due to the reduction of the contact constraint equations.

This lesson is completed. 3-16

Since these faces will separate when the pressure is applied, you can define a Free contact condition between them.

Lesson 11: Analysis of Two Contacting Cantilevers with Rough Surfaces In this lesson, you will learn how to:

q q q q q

Define a Contact/Gaps condition, Specify a friction coefficient for use with contact, List reaction forces and find out forces developed due to friction, Run static analysis, and Visualize the results. Fixed

200 psi normal pressure

Fixed

Description The two cantilevers initially contact each other as shown in the figure. A pressure is applied to the upper face of the upper cantilever. We will mesh this model with a global Node to Node contact condition. The lower cantilever will deform under the action of loads transferred through the contact. The program calculates friction forces at the faces of contacting elements by multiplying the coefficient of friction by the corresponding normal forces. ✍ The lower face of the upper cantilever and the upper face of the lower cantilever are contacting each other partially. COSMOS/Works automatically takes care of this situation by generating compatible meshes on the contacting portions of the two faces.


3-17


n Lesson 11: Analysis of Two Contacting Cantilevers with Rough

Open the Model, Assign Material, and Apply Loads/Restraints 1

Open the Friction assembly located in the Examples\Contact folder of the COSMOS/Works installation directory.

✍ If you do not see the COSMOS/Works menu, click Tools, Add-Ins, select COSMOS/Works and click OK. ✍ We recommend that you click File, Save As to save the assembly with a different name before defining a study so that you can use the original file again. 2

Create a Static analysis study.

3

Make sure to modify the properties of the study to activate the Include Friction flag and enter 0.05 in the Friction Coefficient field. Also make sure to use the Direct Sparse solver.

✍ You can use the FFEPlus solver in cases where each part is adequately restrained (stable) without considering the contact condition. The FFE solver cannot be used with contact problems.

3-18

4

Assign the default Alloy Steel from the COSMOS/M Material Library to both parts.

5

Fix the two far faces of the cantilevers.

6

Apply a normal pressure of 200 psi to the upper face of the upper cantilever.

Mesh the Assembly To define a contact option on the contacting faces: In the COSMOS/Works Manager, right-click the Contact/Gaps icon and select Touching Faces: Node to Node.

✍ Only portions of the two faces are in contact. For proper representation of the contact condition, the mesher treats the contacting portions as if they were separate faces. To mesh the assembly: 1

Right-click the Mesh icon and select Preferences. Use the options shown in the figure.

2


3

In the Global Size field, enter 1.0 inches. ✍ If your preferred unit of length is not inches, make sure to enter an global size equivalent to 1.0 inch.

4

Click OK.

To run the analysis: Right-click the study icon and select Run.


3-19



To visualize stress results: 1

Click the (+) sign to the left of the Stress folder.

2

Double-click the Plot1 icon in the Stress folder.

Gap

Contact

To visualize displacement results:

3-20

1

Click the (+) sign to the left of the Displacement folder.

2

Double-click the Plot1 icon in the Displacement folder.

Reaction Forces Friction forces should develop reaction forces in the Z-direction at the supports. To view the X, Y, and Z directions: Click the FeatureManager tab. 2 Click Plane1. The global X, Y, and Z directions are illustrated in the figure. 1

Y

X

To list reaction forces: 1

Select the left support.

2

Right-click the Displacement folder and select Reaction Forces.

3

From the Units drop-down menu, select lb.

4

Click the Update button.

5

Select the right support.

6


7

Select both supports.

8


Z

Reaction forces at the left support

The total applied force is 200 psi times 80 in2 = 16,000 Pounds (lbs) in the negative Y-direction. Notice that the upward reactions at the left and right supports are 11,057 and 4,943.3 lbs, respectively. A Z-force of about 247.3 lbs develops at both supports due to friction.

✍ Small unbalanced forces develop in the model due to approximations and numerical round-off errors. For example, you can see that, for the entire model, there is an unbalanced Z-force of 0.00021958 lbs, and an unbalanced Xforce of 5.4894e-5 lbs.

Reaction forces at the right support

Reaction forces with both supports


3-21



Results of a Similar Study Without Friction To remove friction: 1

Right-click the study icon and select Properties.

2

Uncheck the Include Friction checkbox.

3

Right-click the study icon and select Run. The stress and displacement results without friction are shown below.


3-22

4 Importing Motion Loads

Introduction Many products contain moving assemblies of components (mechanisms). Mechanisms play a crucial role in the performance of such products. Dynamic Designer/Motion is a design software produced by Mechanical Dynamics, Inc. for the simulation of mechanical systems. Embedded in SolidWorks, it enables designers to model 3D mechanisms as virtual prototypes. After making sure that the mechanism is working properly in Dynamic Designer/ Motion, you naturally want to make sure that the parts of the assembly are safe under the action of the loads generated by the specified motion. COSMOS/Works can automatically import motion loads from the Dynamic Designer/Motion for SolidWorks. This chapter presents a step-by-step lesson on how to define a motion in Dynamic Designer/Motion and run static analysis based on importing motion loads from Dynamic Designer /Motion. This example is intended to provide you with a self-contained document for using Dynamic Designer/Motion for the purpose of calculating motion loads to be used by COSMOS/Works. For formal description of the capabilities of Dynamic Designer /Motion, please refer to the Dynamic Designer/Motion for SolidWorks User ’s Guide and the corresponding on-line help. ✍ To be able to import motion loads to COSMOS/Works, you must install Dynamic Designer/Motion on your system. For more information about Dynamic Designer/Motion, please contact your sales representative at Structural Research and Analysis Corporation.


4-1

Chapter 4 Importing Motion Loads

n Lesson 12: Importing Motion Loads from Dynamic Designer/Motion

Lesson 12: Importing Motion Loads from Dynamic Designer/Motion In this lesson you will learn how to:

q q q q q q q

Open the landing gear assembly, Switch to the Dynamic Designer/Motion environment, Define moving and grounded parts, Define motion, Run the simulation, Export motion results to a spreadsheet, and Transfer the motion loads to COSMOS/Works to perform static analysis and visualize the results.

Description In this tutorial, we will show you how to use Dynamic Designer/Motion and COSMOS/Works to analyze a landing gear assembly mechanism. The landing gear mechanism is part of a retractable nose wheel of a conceptual light aircraft. The main purpose of the mechanism is to bring the gear down to a locked position. The locked position is controlled by a diagonal bracing which, when fully extended, has an electro-mechanical latch to lock it in position. In real-life, the pilot activates a switch to release this latch and a pre-loaded spring ensures that the diagonal brace retracts to the initial position. The actuator can retract the under carriage only when the diagonal brace is free to move. Dynamic loads induced by this motion will be automatically transferred to COSMOS/ Works to perform design analysis.

Link Arm

We will calculate the stresses that develop in the link arm due to motion loads. To demonstrate the tight integration between Solid/Works, Dynamic Designer/ Motion, and COSMOS/Works, we will modify the part and repeat the motion and design simulations after modifying the geometry.

4-2

✍ The magnitudes of the loads generated by the moving mechanism may not be significant compared to loads caused by the impact of landing. You can create another study to simulate the impact of landing.

Load the Landing Gear Model To load the landing gear assembly file: 1

Start SolidWorks.

2


3

Navigate to the folder ...\Examples\Motion, where “...” refers the COSMOS/ Works installation folder.

4

Change the Files of type field to Assembly Files (*.asm; *.sldasm).

5

Select the landing_gear.SLDASM file, and click Open.


4-3



✍ Make sure that the Motion menu appears on SolidWorks menu bar. if you do not see it, click Tools, Add-Ins. In the Add-Ins dialog box, check Dynamic Designer Motion checkbox and click OK. When Dynamic Designer Motion is loaded successfully, a tab will be added at the lower left corner of the SolidWorks window.

Define Moving and Grounded Parts Now we will build the joints and other motion entities for the mechanism in Dynamic Designer. To start the IntelliMotion browser: Click the Dynamic Designer/Motion tab SolidWorks window.

located at the lower left corner of the

To define grounded and moving parts: 1

In the IntelliMotion browser, select mount1-1, mount2-1, and mount3-1 parts.

2

Right-click the selected parts and click Ground Part.

3

Select the remaining parts, click the right button of the mouse, and select Moving Part.

Define Actuator Motion We will specify a motion to the Actuator part. To define motion to the Actuator:

4-4

1

Click the (+) sign to the left of the Actuator-1 part to show its contents.

2

Double-click the Concentric7 cylindrical joint. This will take you to the Joints folder in the IntelliMotion browser.

3

In the Joints folder, right-click the Concentric7 folder and select Properties. The Edit Mate-Defined Joint dialog box opens with the Motion tab selected.

4

In the Motion On field, select Translate Z.

5

In the Motion Type field, select Displacement.

6

Select Harmonic as a function type for the motion from the Function menu.

7

Enter the following numerical values in the corresponding fields.: • -90 (mm) in the Amplitude field, • 9 (deg/sec) in the Frequency field, • 0 (sec) in the Time Offset field, • 90 (sec) in the Phase Shift field, and • -90 (mm) in the Average field.

8

Click

9

Click

to accept the entries. to apply the motion.


4-5



Run the Motion Simulation To set the simulation options: 1

On SolidWorks menu bar, click Motion, Toolbar. The Simulation toolbar opens.

2

Click . The Dynamic Designer Options dialog box opens with the Simulation tab selected.

3

In the Simulation Parameters box, select Duration from the menu, and enter 40 (sec) in its field.

4

In the Number of Frames field, enter 60.

5

Click OK to accept other default settings.

To run the motion simulation: Click the simulation button toolbar, click .

4-6

to start the simulation. To close the Simulation

Export the Results to Spreadsheet To export the motion results to a spreadsheet: 1

On the SolidWorks menu bar, click Motion, Export Results, To Spreadsheet. The Export Results to Excel dialog box opens.

2

In the Elements with Results list box, click the (+) sign to the left of the Concentric7 folder (at the bottom of the list) and select TranslateZ Motion.

3

In the Results Characteristics list box select Force.

4

From the Components list box, select Magnitude.

5

Optional: Enter a name for the plot in the Title field, for example, Force.

6

Click the Add 1 Curves button.


4-7


7


Click OK. The selected results will be plotted in Excel.

✍ Microsoft Excel is required for plotting the curve. However, you still can transfer loads even if you don’t have EXCEL.

Export Motion Loads to COSMOS/Works Next, we will export the motion loads developed in the model to COSMOS/ Works for analysis. However, we need to select a particular time instant at which the loads are to be transferred to COSMOS/Works. To export the motion loads to COSMOS/Works:

4-8

1

Click Motion, Toolbar. The Simulation toolbar opens.

2

Drag the slider to frame number 16 (corresponds to 10 sec).

3

On SolidWorks menu bar, click Motion, Export Results, To COSMOS/Works. The Unassigned Load Entities dialog box opens. Click the Derive Joint Load Entities from Mates button, and then click OK.

4

In the Save As dialog box, select the COSMOS/Works working directory to save the load information file landing_gear_16.txt.

5

Click the simulation button to delete the results and return to the initial position.

6

Close the simulation toolbar and save the assembly.

Read the Load File into COSMOS/Works To import the motion loads to COSMOS/Works: 1

On the SolidWorks menu bar, click COSMOS/Works, Import Motion Loads. The Open dialog box opens.

2

Select the load information file generated in the previous step (i.e., the landing_gear_16.txt file) and click Open.

3

In the Available Loads list, actu_pist-1:Body Forces will be selected. Click it to deselect it, and then click link_arm-1:Body Forces.

4

Click box.

5

Click OK to close the Import Motion Loads dialog box.

to move the link_arm-1:Body Forces to the Selected Loads list

Open the Part in COSMOS/Works 1

Click the FeatureManager tab.

2

Right-click the link_arm<1> icon and select Open link_arm.sldprt. The part will be opened in the graphics area.


4-9


3


Click the COSMOS/Works Manager tab. You will see study Frame-16 with gravity and centrifugal load already applied to the part. This study was created automatically when you imported the motion load file to COSMOS/Works.

Define Materials We will apply Plain Carbon Steel to the link arm part. Right-click the link_arm material icon and select Apply/Edit Material. In the Material dialog box, select Plain Carbon Steel from the Material Name list box and click OK.

Apply Restraints We will fix the two cylindrical faces of the link arm. To fix the inner cylindrical faces:

4-10

1

Select the two faces as shown in the figure.

2


3

In the Restraints dialog box, select Fixed.

4

Click OK.

Fix these two faces

Create the Mesh To set the mesh preferences: 1


2


3


4

In the Mesh Control box, check Smooth Surface.

5

From the Jacobian Check menu, make sure that 4 Points in selected.

6

Click OK.

To mesh the part: Right-click the Mesh icon and select Create. In the Mesh dialog box, click OK to accept the element size suggested by the program.

Run the Analysis Right-click the Frame-16 study icon and select Run. When the analysis is completed, click OK to close the message window.

Visualize the Results To plot stress results: 1

Click the (+) sign next to the Stress folder.

2

Double-click the Plot1 icon to generate the stress plot.


4-11



To animate stress results: 1

Right-click the Plot1 icon under Stress folder and select Animate.

2

In the Animation dialog box click the Play button

to start the animation.

To plot displacement results: 1

In the COSMOS/Works Manager, click the (+) sign next to the Displacement folder.

2

Double-click the Plot1 icon to generate a displacement plot.

Modify the Link Arm Part We will modify the link arm part by creating a cut through the part’s thickness. To modify the part:

4-12

1

Switch to the SolidWorks environment by clicking the FeatureManager tab.

2

Right-click the Mirror1 icon and select Suppress.

3

Right-click the Cut Extrude 1 icon and select Edit Definition. The Cut Extrude Feature dialog box opens.

4

From the Type menu, select Through All.

5

Click OK.

6

Switch to the landing_gear assembly document. Click Yes to rebuild the assembly with the new changes.

The assembly rebuilds with the new changes

Run the Motion Analysis with the Modified Geometry To rerun the analysis with the modified assembly: 1

On the SolidWorks menu bar click Motion, Toolbar. The Simulation toolbar opens.

2

Click the simulation button

3

In the simulation toolbar, drag the slider to frame number 16 and click Motion, Export Results to COSMOS/Works.

4

In the Save As dialog box, browse to the COSMOS/Works working directory and click Save.

5

Click the simulation button to delete the results and return to the initial position.

to run the simulation.

Export Motion Loads to COSMOS/Works To transfer the motion loads to COSMOS/Works: 1 2 3 4 5

6

Click COSMOS/Works, Import Motion Loads. The Open dialog box opens. Select the load file saved in the previous step and click Open. In the Import Motion Loads dialog box, change the study name to Frame-16 Modified. In the Available Loads list box, click the link_arm-1: Body Forces and move it to the Selected Loads list box. In the Selected Loads list box, click actu_pist-1:Body Forces and move it to the Available Loads list box. Click OK.


4-13



Analyze the Part in COSMOS/Works 1

Click the FeatureManager tab.

2

Right-click the link_arm<1> icon and select Open link_arm.sldprt. The part will be opened in SolidWorks graphics area.

3

Click the COSMOS/Works Manager toggle icon. You will see the study Frame-16-Modified with gravity and centrifugal loads already applied to the part.

To assign material properties to the part: 1

Open the Frame-16 study folder and select the Solids folder.

2

Drag and drop it onto the Frame-16-Modified study folder.

Apply Restraints To fix the faces of the holes:

4-14

1

Select the faces of the holes.

2


3


4

Click OK.

To mesh the model: Right-click the Mesh icon and select Create. Click OK to accept the default element size and tolerance suggested by the program. To run the analysis: Right-click the Frame-16-Modified study icon and select Run. After the analysis is completed, click OK to close the message window. To visualize the stress results: 1

Click the (+) sign to the left of the Stress folder under the Frame-16-modified study.

2

Double-click the Plot1 icon. Compare the results with respect to Frame-16 study.


4-15


5 Frequency Analysis Tutorial

This chapter presents step-by-step lessons for performing frequency analysis.

q

Lesson 13: Frequency Analysis of a Bracket Part

q

Lesson 14: Frequency Analysis of a Crank Assembly


5-1

Chapter 5 Frequency Analysis Tutorial

n Lesson 13: Frequency Analysis of a Bracket Part

Lesson 13: Frequency Analysis of a Bracket Part Frequency analysis, also known as modal or dynamic analysis, calculates the resonant (natural) frequencies and the corresponding mode shapes. In this lesson, you will learn how to:

q q q

Create a frequency analysis study, Run frequency analysis, and Visualize the frequency analysis results.

Retrieve the Part To retrieve the part: 1

Start SolidWorks.

2


3

Change the Look in folder to ...\Examples where “...” refers to the COSMOS/Works installation folder.

4


5

Double-click the Tutor1.prt part file. The part file opens.

6

Verify that COSMOS/Works appears in the top menu bar of SolidWorks. ✍ If you do not see the COSMOS/Works menu, click Tools, Add-ins, then click the checkbox for COSMOS/Works and click OK.

5-2

✍ We recommend that you use File, Save As to save the part with a different name before defining a study so that you can use the original file again.

Create a Frequency Analysis Study The first step in performing analysis with COSMOS/Works is to create a design study. We will use the COSMOS/Works Manager to define and manage all aspects of the study. To start the COSMOS/Works Manager: Click the COSMOS/Works Manager icon located at the lower left corner of the window.


✍ To return to the FeatureManager design tree, click the FeatureManager icon . To create a frequency analysis study: 1

Right-click the Tutor1 part icon and select Study. The Study dialog box opens.

2


3

In the New Study field, type in a name for the study, for example, Freq-1.

4

From the Analysis Type drop-down list, select Frequency.

5

In the Mesh Type box, click Solid.

6

Click the OK button to return to the Study dialog box.

7

Click OK.


5-3



Assign Material Properties Assign Material To assign a material from the COSMOS/M Library: 1

In the COSMOS/Works Manager tree, right-click the Tutor1 icon under Solids folder and select Apply/Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type drop-down menu, verify that Steel is selected.

3

In the Material Name list box, verify that Alloy Steel is selected.

4

Click OK.

Apply Restraints To fix the two holes: 1

Select the face of one hole. Press and hold down the Ctrl key and select the face of the other hole.

2

In the COSMOS/Works Manager tree, right-click the Load/Restraint icon and select Restraints. The Restraints dialog box opens.

3

From the Type box, select Immovable.

4

Click OK.

Mesh the Part To set mesh preferences:

5-4

1

In the COSMOS/Works Manager tree, right-click the Mesh icon and click Preferences. The Preferences dialog box opens with the Mesh tab selected.

2


3


4


5

Make sure that 4 Points is selected from the Jacobian Check menu.

6

Click OK.

To mesh the part: 1

Right-click the Mesh icon and select Create. The Mesh dialog box opens and an average element size is suggested.

2

Click OK to accept the default element size. After meshing is completed, you will get the Solid mesh completed message.

3

Click OK. A checkmark appears on the Mesh icon.


In the COSMOS/Works Manager tree, right-click the Mesh icon and select Show Mesh. The mesh is displayed in the SolidWorks window.

2


3

Right-click the Mesh icon and select Details to display information about the mesh.


Run Frequency Analysis To run frequency analysis: 1

Right-click the Freq-1 study icon and click Run. The analysis starts. When the analysis is completed, you will get the Frequency Analysis Completed message.

2

Click OK.


5-5



List and Visualize the Frequency Analysis Results To list frequency results: Click COSMOS/Works, List Results, Mode Shape. The following list will be displayed.

To plot the fundamental mode shape: 1

Click the (+) sign to the left of the Deformation folder. The Plot1 icon appears.

2


To plot other mode shapes:

5-6

1

In the COSMOS/Works Manager, right-click the Deformation folder under the Freq-1 study and select Define. The Deformed Shape Plot dialog box opens.

2

In the Mode Shape No. field, enter 2, 3, etc., to plot other mode shapes.

3

Click OK.



5-7


n Lesson 13: Frequency Analysis of a Crank Assembly

Lesson 13: Frequency Analysis of a Crank Assembly In this lesson you will learn how to:

q q q

Create a frequency analysis study, Run frequency analysis, and Visualize the frequency analysis results.

Retrieve the Part To retrieve the assembly: 1

Start Solid Works.

2


3

Change the Look in folder to ...\Examples where “...” refers to the COSMOS/ Works installation directory.

4

In the Files of type field, select Assembly Files (*.asm; *.sldasm).

5

Double-click the Crank.ASM assembly file.

✍ If you do not see the COSMOS/Works menu, click Tools, Add-ins, then check the control box for COSMOS/Works and click OK.

Create a Frequency Analysis Study To create a frequency analysis study:

5-8

1


2

Right-click the Crank icon, and click Study. The Study dialog box opens.

3


4

In the New Study field, type in a name for the study, for example, Freq-2.

5

From the Analysis Type menu, select Frequency.

6

Click OK to return to the Study dialog box.

7

Click OK.

Assign Material Properties To assign material to the CrankPulley-1 part: 1

Right-click the CrankPulley-1 icon and select Apply/Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type menu, select Iron.

3

From the Material Name list box, select Gray Cast Iron.

4

Click OK.

To assign materials to the other parts: Repeat the steps above to assign the following materials: • Stainless Steel (ferretic) to CrankArmAxle-1, and • Alloy Steel to CrankArm-1 and CrankArm-2.

Apply Restraints To apply loads and restraints to the assembly: 1

Select the outer cylindrical face of the pulley.

2


3

In the Type box, select Immovable (No Translation).

4

Click OK.

Mesh the Assembly To set the meshing properties: 1


2


3


4


5


6

Click OK.


5-9


n Lesson 13: Frequency Analysis of a Crank Assembly

To mesh the assembly: 1

Right-click the Mesh icon and select Create. The Mesh dialog box opens.

2


3

Click Ok. When the meshing is completed, you will get the Solid Mesh completed message.

4

Click OK.

Run the Frequency Analysis To run frequency analysis: Right-click the Freq-2 study, and select Run. The analysis starts. After completing the analysis, the program creates two folders for the Displacement and the Deformation in the Freq-2 study.

List and Visualize the Frequency Analysis Results To list the frequencies:

5-10

1

Click COSMOS/Works, List Results, Mode Shape. The Mode Shape window opens and lists the frequencies.

2

Click Close to close the window.

To plot the first mode: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Deformation folder of Freq-2 study.

2




5-11

6 Buckling Analysis Tutorial

This chapter presents step-by-step lessons for performing buckling analysis.

q q q

Lesson 15: Buckling of Thin Plates Using Shell Elements Lesson 16: Buckling Analysis of a Bar Lesson 17: Buckling Analysis of a Bracket


6-1

Chapter 6 Buckling Analysis Tutorial

n Lesson 15: Buckling of Thin Plates (Shell Models)

Lesson 15: Buckling of Thin Plates (Shell Models) Buckling analysis calculates the buckling (critical) load factors and the corresponding buckling modes. In this lesson, you will learn how to:

q q q q q q q

Use different ways of shell modeling, Create the shells, Assign material and thickness to the shells, Apply restraints and loads to shells, Mesh the shells, Run buckling analysis, Visualize the buckling analysis results by listing critical load factors and plotting buckling modes.

Description of the Problem Three rectangular plates 10” x 2” are connected as shown in the figure. The central plate has a thickness of 0.4”. Each of the other two plates has a thickness of 0.2”.

0.4” thickness

0.2” thickness

6-2

Shell Modeling Options COSMOS/Works offers 3 different procedures to create shell models. First Option: Shell Using Midsurfaces This option requires the creation of a solid model and creating a study selecting the Shell Using Midsurfaces option. The program extracts midsurfaces and assigns thicknesses of different shells automatically. Only one material can be assigned to the part. This option is not available for assemblies. The midsurface of a generated shell element coincides with the associated extracted midsurface. We recommend this option for sheet metals and simple thin parts. Second Option: Shell Using Faces of a Solid This option also requires the creation of a solid part or assembly and creating a study selecting the Shell Using Surfaces option. You can select the faces to be meshed and assign the desired thicknesses and materials. Adjacent shells are bonded automatically. The midsurface of a generated shell element coincides with the associated face. Third Option: Shell Using a Surface Model This option requires the creation of a surface model and creating a study selecting the Shell Using Surfaces option. You can select the faces to be meshed and assign the desired thicknesses and materials. Adjacent shells are bonded automatically. The midsurface of a generated shell element coincides with the associated surface.


6-3


n First Option: Using Midsurfaces

First Option: Using Midsurfaces Retrieve the Part To retrieve the part: 1

Start COSMOS/Works.

2


3


4


5

Double-click the 3plates-midsurfaces part file.

To start the COSMOS/Works Manager: Click the COSMOS/Works Manager icon Solid Works window.


Define a Buckling Analysis Study To define a buckling analysis study:

6-4

1

Right-click the 3plates-midsurfaces icon and select Study. The Study dialog box opens.

2


3

In the New Study field, type in a name for the study, for example, Buckling-1.

4

From the Analysis Type menu, click Buckling.

5

In the Mesh Type box, select Shells using midsurfaces.

6

Click OK. The new study name appears in the Studies list box.

7

Click OK.

Assign Material Properties To assign a material from the COSMOS/M Library: 1

Right-click the 3plates-midsurfaces icon in the Solids folder and select Apply/ Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type menu, verify that Steel is selected.

3


4

Click OK.

Insert Loads and Boundary Conditions In this tutorial, we will fix one end and apply a force of 100 Pounds to the other end.

Apply 100 Pound Force on this face Fix this face

To fix the left end: 1

Select the left end face as shown in the figure.

2

Right-click the Load/Restraint icon and select Restraints. The Restraints dialog box opens.

3

In the Type box, select Fixed.

4

Click OK.

To apply the force: 1

Select the right end face as shown above.

2

Right-click the Load/Restraint icon and select Force. The Force dialog box opens.

3

In the Type box, check Apply Normal Force.

4

From the Distribution box, check Uniform.


6-5



5


6

In the Value field, enter 100 to apply 100 Pounds.

7

Click OK.


Right-click the Mesh icon and select Preferences. The Preference dialog box opens with the Mesh tab selected.

2


3


4


5


6

Click OK.

To mesh the part: 1

Right-click the Mesh icon and select Create. The Mesh dialog box opens and an average element size of 0.37808 inches is suggested.

2

Click OK. After meshing is completed, you will get the Shell Mesh Completed message.

3

Click OK. Meshing starts.

4

Click OK when meshing is completed.

To align the shells: 1

Right-click the Mesh icon and select Show Mesh. The mesh is displayed in the SolidWorks window.

Flip this face

After flipping

2

6-6

Select the left shell.

3

Right-click the Mesh icon and select Flip Shell Elements.

✍ You may get different misaligned shells based on the version or service pack of SolidWorks that you are using. You need to align all shells before running the analysis. 4

Right-click the Mesh icon and select Hide Mesh to hide the mesh.


Run Buckling Analysis To run buckling analysis: 1

In the COSMOS/Works Manager tree, right-click the Buckling-1 study icon and select Run. Analysis starts. When the analysis is completed, you will get the Buckling Analysis Completed message.

2

Click OK when analysis is completed.

List and Visualize Buckling Results To list buckling results: 1

Click COSMOS/Works, List Results, Mode shape. The buckling load factor is listed as 1.54

2

Click Close to close the Mode Shape list box.

To plot the buckling mode: 1

In the COSMOS/Works Manager tree, click the (+) sign to the left of the Deformation icon.

2


To animate the mode shape: 1

Right-click the Plot1 icon under the Deformation folder and select Animate. The Animation dialog box opens.

2


3



✍ You can save the animation as an AVI file and view it with the Media Player by checking the corresponding checkboxes.


6-7



Calculate the Buckling Load The buckling load factor (BLF) is defined as the ratio of the critical buckling load to the applied loading. You can think of the BLF as a factor of safety against buckling. A BLF less than unity indicates that the model is not safe under the specified loading. The following table illustrates the interpretation of possible BLF values. BLF Value

Buckling Status

Notes

1 < BLF

COSMOS/Works does not predict buckling.

The applied loading is less than the estimated critical loading.

0 < BLF < 1 COSMOS/Works predicts buckling to occur.

The applied loading exceeds the estimated critical loading.

BLF = 1

COSMOS/Works predicts buckling to occur.

The applied loading is equal to the estimated critical loading.

BLF = -1


COSMOS/Works will predict buckling if you reverse the direction of loading.

-1 < BLF < 0


COSMOS/Works would predict buckling if you were to reverse the direction of loading.

BLF < -1


COSMOS/Works will not predict buckling even if you reverse the direction of loading.

To calculate the buckling load: Critical load factor

= 1.54

Critical buckling load

= 100 (applied force) x 1.54 = 154 Pounds

6-8

Second Option: Using Faces of a Solid Retrieve the Part To retrieve the part: 1

Start COSMOS/Works.

2


3


4


5

Double-click the 3plates-faces part file.



Define a Buckling Analysis Study To define a buckling analysis study: 1

Right-click the 3plates-faces icon and select Study. The Study dialog box opens.

2


3


4

From the Analysis Type menu, select Buckling.

5

In the Mesh Type box, select Shell using surfaces.

6


7

Click OK.


6-9


n Second Option: Using Faces of a Solid

Define the Shells To define the 3 shells: 1

Select the 3 faces shown in the figure.

2

Right-click the Shells folder icon in the COSMOS/Works Manager tree and select Define by Selected Surfaces. The Define Shell dialog box opens. Select these 3 faces

This dimension is irrelevant

3

From the Units drop-down menu, select in (Inches).

4

In the Value field, type in 0.2.

5

Click OK. The program creates an icon for each of the 3 faces in the Shells folder.

To modify thickness of the middle shell: 1

In the Shells folder, click the Shell-2 icon. The middle shell highlights.

2

Right-click the Shell-2 icon and select Edit Definition.

3


4


5

Click OK. The program changes the thickness of the middle shell from 0.2” to 0.4”.


Right-click the Shells folder icon and select Apply Material to All. The Material dialog box opens with the COSMOS/M Library tab selected.

2


3


4

Click OK. ✍ You can assign a different material to each shell.

6-10

Insert Loads and Boundary Conditions Applying loads and restraints on the end faces, as performed in the midsurface study, will not work with this option. We will apply the restraint and force to the edges of the shells instead as follows: To fix the left edge: 1

Select the left edge of left shell as shown in the figure.

2


✍ Notice that the Selected Entities box lists the number of selected faces, edges and vertices. In this case, one edge is selected. 3


4

Click OK.

To apply the force: 1

Select the right edge of the right shell face as shown in the figure.

2


3

From the Units drop-down menu, select English (IPS).

4

Click the Along plane Dir1 (of Plane 1) checkbox and enter -100 in its field.

5

Click OK.

Mesh the Part, Run the Analysis, and Visualize the Results The rest of the steps are similar to the previous study: 1

To mesh the part, right-click the Mesh folder icon and select Create. Use the default global element size of 0.74002”.

2

Right-click the Mesh icon and select Show Mesh. If needed, align the shell elements by selecting the misaligned face, right-clicking the Mesh icon, and selecting Flip Shell Elements.

3

Right-click the Mesh icon and select Hide Mesh.

4

To run buckling analysis, right-click the study folder and select Run.


6-11


n Third Option: Using Reference Surfaces

5

When analysis is completed, click OK.

6

To list buckling results, click COSMOS/Works, List Results, Mode Shape. The buckling load factor is listed as 1.54.

✍ The small difference in the result is due to differences in geometry modeling and the default global element size used in meshing. The default global element size in the this case is almost twice the default global element size in the first case. The results indicate that the solution has converged to the correct answer.

Third Option: Using Reference Surfaces Retrieve the Part To retrieve the part: 1

Start COSMOS/Works.

2


3

Change the Look in folder to ...\Examples where “...” refers to the COSMOS/Works installation folder.

4


The model consists of 3 surfaces

5

Double-click the 3plates-surfaces part file. The part is made up of 3 reference surfaces.

6

Click the surfaces to identify the 3 surfaces.


6-12


Define a Buckling Analysis Study To define a buckling analysis study: 1

Right-click the 3plates-Surfaces icon and select Study. The Study dialog box opens.

2


3


4

From the Analysis Type menu, select Buckling.

5

In the Mesh Type box, select Shell using surfaces.

6


7

Click OK.

Define the Shells To define the 3 shells: 1

Right-click the Shells folder icon in the COSMOS/Works Manager tree and select Define by All Ref Surfaces . The Define Shell dialog box opens.

2


3


4

Click OK. The program creates an icon for each of the 3 surfaces in the Shells folder.

To modify thickness of the middle shell: 1

In the Shells folder, click the Shell-3 icon. The middle shell highlights.

2

Right-click the Shell-3 icon and select Edit Definition.

3



6-13


n Third Option: Using Reference Surfaces

4


5

Click OK. The program changes the thickness of the middle shell from 0.2” to 0.4”.


Right-click the Shells folder icon and select Apply Material to All. The Material dialog box opens with the COSMOS/M Library tab selected.

2


3


4

Click OK. ✍ You can assign a different material to each shell.

Insert Loads and Boundary Conditions We will apply the restraint and force to the edges as follows: To fix the left edge: 1

2

Select the left edge of left shell as shown in the figure.

Apply 100 Pounds on This Edge


✍ Notice that the Selected Entities box lists the number of selected faces, edges and vertices. In this case, one edge is selected. 3


4

Click OK.

Fix This Edge

To apply the force:

6-14

1

Select the right edge of the right shell face as shown in the figure above.

2


3


4

Click the Normal to plane (Plane 1) checkbox and enter -100 in its field.

5

Click OK.

Mesh the Part, Run the Analysis, and Visualize the Results The rest of the steps are similar to the previous study: 1

To mesh the part, right-click the Mesh folder icon and select Create. Use the default global element size of 0.23238”.

2

Right-click the Mesh icon and select Show Mesh. If needed, align the shell elements by selecting the misaligned surface, right-clicking the Mesh icon, and selecting Flip Shell Elements. ✍ You can specify a global element size larger than the default. We have seen in the previous studies that element sizes of about 0.38 and 0.74 inches gave similar results.

3

Right-click the Mesh icon and select Hide Mesh.

4

To run buckling analysis, right-click the study folder and select Run. When analysis is completed, click OK.

5

To list buckling results, click COSMOS/Works, List Results, Mode shape. The buckling load factor is listed as 1.5332.

✍ The small difference in the result is due to differences in geometry modeling and the default global element size used in meshing. The default global element size in the this case is smaller than the default global element sizes in the first and second studies. The results indicate that the solution has converged to the correct answer.



6-15

Lesson 16: Buckling Analysis of a Bar In this lesson, you will learn how to:

q q q q q q q

Verify the dimensions of your model, Create a buckling analysis study, Assign material to the part, Apply loads and boundary conditions, Mesh the part, and Run buckling analysis, Visualize the buckling analysis results, and calculate the buckling load.

Fixed end

Bar dimensions are 1”X1”X20” 1,000 pound force

Opening the Bar Part To open the part:

6-16

1

Start SolidWorks.

2

From the File menu, click Open.

3


4

Click the Examples folder.

5

Choose the Bar.SLDPRT file.

6

Click Open. COSMOS/Works User’s Guide

Verifying the Dimensions of the Model We recommend that you verify the dimensions of your model before creating analysis studies. To verify the length of the bar: 1

Select one of the long edges of the bar.

2

Click Tools, Measure. The length should be 20 inches.

3

Close the Measure dialog box.

4

Verify that the cross section is 1 inch by 1 inch.

Creating a Buckling Analysis Study The first step in performing analysis with COSMOS/Works is to create a design study. To create a buckling analysis study: 1

In the menu bar, click COSMOS/Works, Study. - or In the COSMOS/Works Manager, right-click the Bar icon in the Solids folder and select Study. The Study dialog box opens.

2


3

In the New Study field, type in the name of the study, for example, Buckling Study.

4

From the Analysis Type drop-down menu, choose Buckling.

5

In the Mesh Type box, select Solid.

6

Click OK. The new study name appears in the studies list box.

7

Click OK.


6-17


n Lesson 16: Buckling Analysis of a Bar

Assigning Material To assign a material from the COSMOS/M Library: 1

In the COSMOS/Works Manager, right-click the Bar icon and select Apply/Edit Material.

2

Click the COSMOS/M Library tab.

3

From the Material Type drop-down menu, select Steel.

4

From the Material Name list box select Alloy Steel.

5

Click OK. ✍ Notice the checkmark that appears on the part icon indicating that you have assigned a material to the part successfully.

Defining Loads and Boundary Conditions We will fix one end of the bar and apply a 1,000 pound force to the other end. To apply a uniform force to the right end of the bar: 1

Select the face at the right end of the bar.

2

Right-click the Loads/Restraint folder and select Force.

3

In the Type box, check the Apply Normal Force option.

4


5


6

In the Value field, enter 1000 to apply a compressive 1,000 pound force.

7

Click OK.

To fix the left end of the bar:

6-18

1

Rotate the bar to make the left end visible.

2

Select the face at the left end of the bar.

3


4


5

Click OK.

Meshing the Model To set mesh preferences: 1


2


3


4


5

Make sure that 16 Points is selected in the Jacobian Check drop-down menu.

6

Click OK.

To mesh the part: 1


2

Drag the slider to the extreme left to use an element size that is twice as the suggested size.

3

Click OK. When meshing is completed, click OK.


Right-click the Mesh icon and select Show Mesh.

2


You are now ready to run buckling analysis.


6-19


n Lesson 16: Buckling Analysis of a Bar

Running Buckling Analysis To run buckling analysis: 1

Right-click the Buckling Study icon. A right-mouse menu opens.

2

Click Run. Analysis starts. When analysis is completed, click OK.

Visualizing the Results of Buckling Analysis To plot the buckling mode: Double-click the Plot1 icon in the Deformation folder. To list the buckling load factor: Click COSMOS/Works, List Results, Mode Shape . Buckling Load Factor The buckling load factor (BLF) is defined as the ratio of the critical buckling load to the applied loading. You can think of the BLF as a factor of safety against buckling. A positive BLF less than unity indicates that the model is not safe under the specified loading. To calculate the buckling load: BLF = 15.678 Estimated buckling load = (BLF) (Applied Loading) = 15.678 x 1000 = 15,678 pound force Theoretical buckling load (Euler’s buckling load) = (π)2 (EI)/(4L2) = 15,421 Pound force Where L E I Error

= 20 inches = Modulus of Elasticity = 30e7 psi = moment of inertia of the cross section = 14/12 in4 = 1.67%


6-20

Lesson 17: Buckling Analysis of a Bracket Part Buckling analysis calculates the buckling (critical) load factors and the corresponding buckling modes. In this lesson, you will learn how to:

q q q q q q q

Retrieve a part and create a buckling analysis study, Assign material to the part, Insert restraints and pressure loading, Mesh the part, Run buckling analysis, Visualize the buckling analysis results by listing critical load factors and plotting buckling modes, and Remesh the part with mesh controls, rerun the analysis, and compare the results.

Retrieve the Part To retrieve the part: 1

Start COSMOS/Works.

2


3


4


5

Double-click the Tutor2 part file.




6-21


n Lesson 17: Buckling Analysis of a Bracket Part

Create a Buckling Analysis Study To create a buckling analysis study: 1

Right-click the Tutor2 icon and select Study. The Study dialog box opens.

2


3


4

From the Analysis Type menu, click Buckling.

5


6


7

Click OK.

Preprocessing Assign Material Properties To assign a material from the COSMOS/M Library: 1

Right-click the Tutor2 icon in the Solids folder and select Apply/Edit Material. The Material dialog box opens with the COSMOS/M Library tab selected.

2


3


4

Click OK.

Insert Loads and Boundary Conditions

Apply pressure normal to this face

In this tutorial, we will fix the hole and the face shown in figure, and apply pressure normal to the top planar face. Fix this face

To fix the hole: 1

Select the hole face.

2


Fix this hole

✍ Notice that the Selected Entities box lists the number of selected faces, edges and vertices. In this case, one face is selected. 6-22

3


4 Optional: To

change the color of the restraint symbol, click the Color button. The Color palette opens. Select the desired color and click OK.

5

Click OK.

To fix the end face: 1

Select the end face of the angle as shown in the figure.

2


3


4

Click OK.

To apply uniform pressure: 1

Select the top planar face as shown in figure.

2

In the COSMOS/Works Manager tree, right-click the Load/Restraint folder and select Pressure. The Pressure dialog box opens.

3

In the Type box, select Normal to selected face.

4

From the Distribution box, select Uniform.

5


6

In the Value field, enter 100 to apply 100 psi.

7

Click OK.


6-23





2


3


4


5


6

Click OK.

To mesh the part: 1


2


3

Click OK. After meshing is completed, you will get the Solid Mesh Completed message.

4

Click OK.


Right-click the Mesh icon and select Show Mesh. The mesh is displayed in the SolidWorks window.

2



Running Buckling Analysis To run buckling analysis:

6-24

1

In the COSMOS/Works Manager tree, right-click the Buckling-1 study icon and select Run. Analysis starts. When the analysis is completed, you will get the Buckling Analysis completed message.

2

Click OK.

List and Visualize the Buckling Results To list buckling results: 1

Click COSMOS/Works, List Results, Mode Shape. The buckling load factor is listed as 692.69.

2

Click Close to close the Mode Shape list box.

To plot the buckling mode: 1


2


To animate the mode shapes: 1

Right-click the Plot1 icon under the Deformation folder and select Animate. The Animation dialog box opens.

2

Click the right arrow button animation.

3

Click the square button animation.

to start the to stop the

✍ You can save the animation as an AVI file and view it with the Media Player by checking the corresponding checkboxes. Calculate the Buckling Load The buckling load factor (BLF) is defined as the ratio of the critical buckling load to the applied loading. You can think of the BLF as a factor of safety against buckling. A BLF less than unity indicates that the model is not safe under the specified loading. The following table illustrates the interpretation of possible BLF values. To calculate the buckling load: Critical load factor

= 692.69

Critical buckling load

= 100 (applied pressure) x 692.69 = 69,269 psi


6-25



✍ You can reduce the error by rebuilding the mesh using a smaller global element size and rerunning the study again.

Remesh the Model With Mesh Control Now we will remesh the model using the Automatic Transition option. To set the mesh preferences: 1

Right-click the Mesh icon, and select Preferences. The Preferences dialog box opens with the Mesh tab selected.

2

In the Mesh Control box check the Automatic Transition checkbox.

3

Click OK.

To mesh the model: 1

Right-click the Mesh icon and select Create. A message window opens that warns you of the deletion of the previous results when remeshing the model. Click OK.

2

In the Mesh dialog box, enter 0.25 in the Global Size field.

3

Click OK.

The Transition Mesh Option

6-26

Rerun the Analysis Run the buckling analysis with the active mesh options by right-clicking the Buckling-1 icon and selecting Run.

Visualize the Buckling Results To plot the buckling mode: 1


2


To calculate the buckling load: Critical load factor = 686.87 Critical buckling load= 100 (applied pressure) x 686.87 = 68,687 psi


6-27


7 Thermal Analysis Tutorial

This chapter presents step-by-step lessons for performing thermal analysis.

q q q q

Lesson 18: Steady State Analysis of a Computer Chip Lesson 19: Transient Analysis of the Computer Chip Lesson 20: Thermal Stress Analysis of the Computer Chip Lesson 21: Steady State Thermal Analysis of a Pipe with Fins


7-1

Chapter 7 Thermal Analysis Tutorial

n Lesson 18: Steady State Thermal Analysis of a Computer Chip

Lesson 18: Steady State Thermal Analysis of a Computer Chip In this lesson you will learn how to:

q q q q q q

Retrieve an assembly and create a thermal analysis study, Assign a material to each part of the assembly, Define thermal loads and boundary conditions, Mesh the Assembly, Run thermal analysis, and Visualize the results.

Introduction Electronic components very often become the hottest spots in many electronic systems. The heat generated by electronic components transfers throughout the electronic system and can cause potential problems. Thermal analysis, therefore, provides you with valuable information for your electronic system designs. Heat transfers by conduction, convection, and radiation. Most electronic systems experience all these modes of heat transfer, though only one of them may dominate a particular design condition. For example, radiation becomes significant at high temperatures but may be negligible at low temperatures. In this lesson, we will analyze the heat transfer in an electronic chip. Any such chip has many electronic components-such as diodes, transistors, resistors, and capacitors-all integrated in a single chip. A chip carrier or substrate, made of ceramic, plastics, or glass, protects it from diverse environmental effects. The carrier receives heat transferred from the chip and then transfers it to the chip case. This process takes place, primarily, through a combination of conduction and convection.

7-2

Description of the Model The assembly has the following parts:

q q

Substrate: rectangular block with dimensions 40x40x1 mm. 16 chips: each is a rectangular bock with dimensions 6x6x0.5 mm.

q

The material of the Substrate is Ceramic Porcelain.

q

The coefficient of thermal conductivity of the chip (k) = 130 W/m oC.

q

The specific heat of the material of the chip = 670 J/kgm/oK

q

The elasticity modulus of the material of the chip =4.1e+11 N/m2.

q

Power dissipated in each chip = 0.2 W.

q

Convection heat transfer coefficient (Film coefficient) = 25 W/m2 oC.

q

Bulk temperature = 300 oK.

Due to the symmetry of the model, we will analyze one quarter of it and apply symmetric boundary conditions at the physical boundaries of the model.

Retrieve the Model To retrieve the assembly: 1

Start COSMOS/Works.

2


3

Change the Look in folder to ...\Examples\Thermal where “...” refers to the COSMOS/Works installation folder.

4

From the Files of type menu, select Assembly Files (*.asm, *.sldasm).


7-3


5


Double-click COMPUTER_CHIP assembly file.

Create a Thermal Analysis Study Start the COSMOS/Works Manager, click the COSMOS/Works Manager toggle button . To create a thermal analysis study:

7-4

1

Right-click the COMPUTER_CHIP icon and select Study. The Study dialog box opens.

2

Click Add. The Study name dialog box opens.

3

In the New Study field, enter a name for the study, for example, Thermal-1.

4

From the Analysis Type menu, select Thermal.

5


6


7

Click OK.

Assign Material Properties to the Parts of the Assembly As we mentioned before, we will assign Ceramic Porcelain from COSMOS/M library to the Substrate, but we will enter the numerical value of the coefficient of thermal conductivity, specific heat, and the elasticity modulus of the chip material manually. To assign material properties to the Substrate: 1

Right-click the Substrate-1 icon under the Solids folder and select Apply/Edit Material. The Materials dialog box opens with the COSMOS/M Library tab selected.

2

From the Material Type menu, select Other Non-metals.

3

From the Material Name list box, select Ceramic Porcelain.

4

Click OK.

To enter material properties for the chips manually: 1

Right-click the Chip-1 icon under the Materials folder and select Apply/Edit Material.

2

Click The Input Properties tab.

3

From the Material Property Name list box, select KX Thermal conductivity.

4

From the Unit System menu, select SI.

5

In the Input Property Value field, enter 130 and click Set.

6

Repeat steps 3-5 to enter the numerical values for the elastic modulus (EX=4.1e11) and specific heat (C=670).

7

Click OK.

8

Repeat steps 1-7 to input material properties for the other chips in the assembly.

✍ We will use the specific heat C when running transient analysis on the assembly (lesson 19), and the elasticity modulus EX when running thermal stress analysis (lesson 20) later in this tutorial.

Apply Thermal Loads and Boundary Conditions We will apply the following thermal loads and boundary conditions to the assembly:


7-5


q q q


A symmetric thermal boundary conditions (zero heat flux) at the planes of symmetry of the assembly (the highlighted faces in figure). Convection boundary conditions at the opposite faces and the bottom face of the assembly. Heat power (volume heat) to the four chips on the substrate face. Apply heat power to these four components

Apply zero heat flux to these faces (planes of symmetry of the model).

To apply symmetric thermal boundary conditions on the planes of symmetry of the model: 1

Select the two faces shown in figure.

2

Right-click the Load/Restraint folder, and select Heat Flux. The Heat Flux dialog box opens.

3

In the Heat Flux field, type in 0.

4

Click OK.

To apply convection boundary conditions to the other faces of the assembly:

7-6

1

Select the opposite faces and the bottom face of the assembly.

2

Right-click the Load/Restraint folder, and select Convection. The Convection dialog box opens.

3

From the Units menu, make sure that SI is selected.

4

In the Film Coefficient field, enter 25.

5

In the Bulk Temperature field, enter 300.

6

Click OK.

To apply heat power boundary condition to the top faces of the chips: 1

Under the Solids folder, select Chip-1, Chip-2, Chip-3, and Chip-4. Press and hold the Ctrl key while selecting these components.

2

Right-click the Load/Restraint folder and select Heat Power. The Heat Power dialog box opens.

3

In the Units menu, make sure that SI is selected.

4

In the Heat Power field, enter 0.2.

5

Click OK.

Mesh the Model To set the mesh preferences: 1

Right-click the Mesh icon, and select Properties. The Preferences dialog box opens with the Mesh tab selected.

2


3


4


5


6

Click OK.



2

Click OK to accept the defaults. The meshing starts, when completed, a Solid Mesh Completed message appears.


7-7


3


Click OK to close the message window.

Run the Analysis To run the thermal analysis on the assembly: 1

Right-click the Thermal-1 study icon and select Run. The analysis starts. When completed, a Thermal Analysis Completed message appears.

2


Visualize the Results of Thermal Analysis To plot temperature distribution on the assembly: 1

7-8

Click the plus sign to the left of the Thermal folder.

2


This lesson is completed. The next lesson will use the same assembly.


7-9


n Lesson 19: Transient Thermal Analysis of the Computer Chip

Lesson 19: Transient Thermal Analysis of the Computer Chip In this lesson you will learn how to:

q q q q

Create a transient thermal analysis study, Define thermal loads and boundary conditions by drag and drop, Run transient thermal analysis, and Visualize results of thermal analysis at different time steps.

Introduction Steady state analysis gives you thermal results when the model reaches thermal equilibrium and the temperature of each particle remains constant afterwards. Steady state analysis does not tell you how long it takes to reach this condition. Transient analysis, on the other hand, answers questions such as: what will be the temperature profile after a given period of time?. In this lesson, you will learn how to perform transient thermal analysis on the computer chip assembly. In this kind of analysis, the temperature changes with time and we will be interested in calculating the temperature distribution in the chip at different instances of time. Since the model and boundary conditions are the same as those used during the steady state lesson (lesson 18), we will use drag and drop procedure to ease the process of assigning the materials and applying the loads and boundary conditions.

Create a Transient Thermal Analysis Study To create a transient analysis study:

7-10

1

Right-click the COMPUTER_CHIP icon at the top of the COSMOS/Works Manager and select Study. The Study dialog box opens.

2


3

In the New Study field, enter a name for the study, for example, Thermal-2.

4


5


6


7

Click OK.

To set the properties of the thermal study to the transient option: 1

Right-click the Thermal-2 study icon and select Properties. The Thermal dialog box opens.

2

In the Solution Type box, select Transient.

3

In the Total Time field, enter 300 (seconds).

4

In the Time Increment field, enter 25.

5

In the Initial Temperature field, enter 300 OK.

6

Click OK.

Assign Materials to the Assembly by Drag and Drop To assign materials to the assembly parts: 1

Click the (+) sign to the left of the Thermal-1 study icon to expand the study items.

2

Drag the Solids folder from Thermal-1 study and drop it onto Thermal-2 study icon. The materials will be copied from Thermal-1 to Thermal-2.

Apply Thermal Loads and Boundary Conditions by Drag and Drop To apply thermal loads and boundary conditions: 1

Click the plus sign to the left of the Thermal-1 study icon to expand the study items.

2

Drag the Load/Restraint folder from Thermal-1 study and drop it onto Thermal-2 study icon. The thermal loads and boundary conditions will be copied from Thermal-1 to Thermal-2.


7-11


n Lesson 19: Transient Thermal Analysis of the Computer Chip

Run Transient Analysis To run the transient thermal analysis: 1

Right-click the Thermal-2 study icon and select Run. The analysis starts. When completed, a Thermal Analysis Completed message appears.

2


Visualize the Transient Thermal Analysis Results Here we are interested in plotting the temperature profiles at different time instants. We will plot the temperature profiles at the first, third, ninth, and the last time steps. To plot the temperature profile after the first time step (after 25 seconds):

7-12

1

Click the plus sign to the left of the Thermal folder. Plot1 icon appears.

2

Right-click the Plot1 icon, and select Edit Definition. The Thermal Plot dialog box opens.

3

In the Time Step No.field, enter 1.

4

Click OK.

To plot the temperature profile after the third, ninth, and the last time step: 1

Right-click the Thermal folder under Thermal-2 study icon, and select Define. The Thermal Plot dialog box opens.

2

In the Time Step No. field, enter 3.

3

Click OK.

4

Repeat steps 1-3 to plot temperature profiles at other times steps (by entering 9 and 12 respectively in the Time Step No. field in the corresponding dialog box).

This lesson is completed. The next lesson uses the same document.


7-13


n Lesson 20: Thermal Stress Analysis of the Computer Chip

Lesson 20: Thermal Stress Analysis of the Computer Chip In this lesson you will learn how to:

q q q q

Create a static analysis study to find out the stresses generated by thermal loading from thermal studies, Define restraints, Run the analysis, and Visualize stress results due to thermal loading.

Create a Thermal Stress Analysis Study To create a thermal stress analysis study: 1

Create a static analysis study with any name, for example, Thermal Stress.

2

Right-click the Thermal Stress study icon and select Properties. The Static dialog box opens.

7-14

3

Check the Include Thermal Effects checkbox.

4

In the Thermal Options box, Select Temperatures from thermal study.

5

From the Thermal Study menu, select Thermal-1 (here we will use the thermal results from the Thermal-1 study).

6

In the Reference temperature at zero strain field, enter 300 oK.

7

Accept the rest of the defaults and click OK.

Assign Materials to the Assembly Parts by Drag and Drop Use the drag and drop technique to copy material properties from Thermal-1 (or equivalently, Thermal-2) study to Thermal Stress study.

Apply Restraints to the Assembly We will fix the free faces of the assembly and apply symmetry boundary conditions to the faces coincident with the planes of symmetry of the model. Fix these faces

Face 2 Face1 Apply structural symmetry boundary condition on these faces.

To restrain the free faces of the chip assembly: 1

Select the free faces of the chip assembly (shown as dotted lines in the figure).

2


3

Select Immovable (No Translation).

4

Click OK.

To apply structural symmetry boundary condition to faces on the planes of symmetry of the model (faces 1 and 2 in the figure): 1

Switch to the FeatureManager and select Plane1.

2

Switch back to the COSMOS/Works Manager, and select Face 1 while pressing the Ctrl key down.

3



7-15


n Lesson 20: Thermal Stress Analysis of the Computer Chip

4

Select Use Reference Plane or Axis . make sure that Plane 1 appears in the Selected Reference box.

5

Under Displacement, check Along plane Dir 1 and enter 0 in its field.

6

Click OK.

7

Select Face 2 of the chip and repeat steps (1-5) mentioned above except that in step 4 check Along plane Dir 2.

Run the Thermal Stress Analysis To run thermal stress analysis: 1

Right-click Thermal Stress study icon and select Run.

2

When the analysis is completed, click OK to close the message window.

Visualize Stresses Due to Structural and Thermal Loadings To plot von Mises stresses:

7-16

1

Click the plus sign to the left of the Stress folder. Plot1 icon appears.

2

Right-click Plot1 icon and select Edit Definition. The Stress Plot dialog box opens.

3

Select psi from the Stress Units menu under the Properties tab.

4

Click the Settings tab, and enter 1 in the Scale Factor field.

5

Click OK.

This lesson is completed. You can close this document. The next lesson uses different document.


7-17


n Lesson 21: Steady State Thermal Analysis of a Pipe with Fins

Lesson 21: Steady State Thermal Analysis of a Pipe with Fins In this lesson you will learn how to:

q q

Use the Split Line function for the proper application of boundary conditions, and Specify thermal boundary conditions and run thermal analysis.

Introduction Convection is the mode of energy transfer between a solid surface and an adjacent moving fluid or gas. It involves the combined effects of conduction and fluid motion. The rate of heat transfer from a surface at a temperature Ts to a surrounding medium at T m is given by the simple law: · Q convection = hA ( Ts – Tm )

When the temperatures Ts and Tm are fixed by design considerations, as is often the case, there are two ways to increase the rate of heat transfer: to increase the convection heat transfer h or increase the surface area A. Increasing h may require the installation of a pump or a fan. This approach may or may not be practical. The alternative is to increase the surface area by attaching extended surfaces called fins made of highly conductive materials such as aluminum. Finned surfaces are commonly used in practice to enhance heat transfer, and they often increase the rate of heat transfer considerably. In the analysis of fins, we consider steady operation with no heat generation in the fin, and we assume the thermal conductivity k of the material to be constant. We also assume the heat transfer coefficient h to be constant and uniform over the entire surface of the fin. In this lesson we will analyze the effect of adding a fin on the steady state temperature distribution in a heating pipe, where a heating fluid carries heat from a heat source to a destination. A portion of the pipe is shown in the figure along with its dimensions.

7-18

Pipe

Fins

For the convenience of the analysis, we will assume that there is no significant change in the fluid temperature as it moves along the pipe. Moreover, we will assume that the heat Heating_Pipe Assembly transfer coefficient h is the same for all surfaces. In performing the analysis, we will use the portion shown in the figure as a representative of the whole assembly due to repetitive symmetry.

Description The assembly consists of the following components:

q q

An 8-mm long stainless steel pipe with an outer radius of 15 mm and an inner radius of 13 mm. A 2-mm thick aluminum fin (alloy # 2024) with an outer radius of 30 mm attached to the surface of the pipe.

We will apply the following thermal loads and boundary conditions to the assembly:

q

The inner face of the pipe is maintained at a fixed temperature of Ts=180 oC.

q

The ambient temperature far enough from the assembly is Tm= 25 oC.

q q

The heat transfer coefficient (h) of the outer face of the pipe (without fin) is 60 W/m2 oC. The heat transfer coefficient (h) for the whole assembly (pipe + fin) is 50 W/m2 o C

Retrieve the Assembly To retrieve the assembly: 1

Start SolidWorks.

2


3

Change the Look in folder to ...\Examples\Thermal where “...” refers to the COSMOS/Works installation folder.

4

From the Files of type menu, select Assembly Files (*.asm; *.sldasm).


7-19


5


Double-click Heating_Pipe assembly file.

Splitting the Outer Face of the Pipe For the proper application of the convection boundary condition to the outer face of the pipe, we need to split it into three faces as shown in the figure. We will use the Split Line function of SolidWorks to do so.

Face 1

Face 2

Face 3

To split the outer face of the pipe:

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Splitting the outer face of the pipe into three faces using Split Line function

1

Right-click the Pipe<1> part in the FeatureManager and select Edit Part.

2

Click the plus sign to the left of the Pipe<1> icon to expand its items.

3

Click Plane1 under the Pipe<1> icon.

4

Click the Sketch tool sketch on Plane1.

to open a

5

While pressing the Ctrl key, select the outer circular edge of the upper face of the fin.

6

Click the Convert Entities tool to project the selected edge onto Plane1.

7

From the menu bar click Insert, Curve, Split Line or click the Split Line tool on the Curves toolbar. The Split Lines dialog box opens.

8

Make sure that Projection is selected in the Types of split box. Click Next.

9

In the Project Split Line dialog box, click inside the Faces to split box and select the outer face of the pipe. Click Finish. The face is split into two faces.

10

Repeat steps (3-9) this time using the lower circular edge of the fin and the lower portion of the outer face of the pipe. When you are done, the outer face of the pipe will be split into three faces.

11

Close the editing mode of the Pipe part by clicking .

12

Click the Rebuild tool

Select this edge of the fin (step 5)

Projection of the selected edge on Plane1 (step 6)

Select the outer face of the pipe to split (step 9)

.

Performing the Analysis on the Pipe Part We will first perform thermal analysis on the Heating_Pipe assembly without fin. To do so, we will open the Pipe part in SolidWorks. To open the Pipe part: While in the FeatureManager, right click the Pipe<1> icon and select Open pipe.sldprt. The part will open in SolidWorks. Learning to Use COSMOS/Works

7-21



Create a Thermal Study To create a thermal analysis study: 1

Start the COSMOS/Works Manager by clicking the icon

.

2

Right-click the Pipe icon at the top of the COSMOS/Works Manager and select Study. The Study dialog box opens.

3


4

In the New Study field, enter a name for the study, for example, No Fin.

5


6


7

Click OK to return to the Study dialog box.

8

Click OK.

Assign Material to the Pipe Part Right-click the Solids folder and select Apply Material to All. Select Alloy Steel from the COSMOS/M Material Library.

Apply Thermal Loads and Boundary Conditions To apply a temperature boundary condition to the pipe’s inner face: 1

Select the pipe’s inner face.

2

Right-click the Load/Restraint icon and select Temperature. The Temperature dialog box opens.

3

From the Units menu, select Celsius.

4

In the Temperature field, enter 180.

5

Click OK.

Apply fixed temperature to this face

To apply convection boundary conditions to the outer faces of the pipe:

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1

Select the three faces on the outer boundary of the pipe.

2

Right-click the Load/Restraint icon and select Convection. The Convection dialog box opens.

3

Make sure that SI is selected from the Units menu.

4


5


6

Click OK.

Mesh the Model To set the Mesh preferences:

Apply convection boundary conditions to these faces

1


2


3


4


5


6

Click OK.



2

Click OK to accept the default mesh size.

Run Thermal Analysis Right-click the icon of the study and select Run.

Visualize the Resultant Heat Flux Plots To plot a section view of the resultant heat flux distribution: 1

Click the (+) sign to the left of the Thermal folder.

2

Right-click Plot1 icon and select Edit Definition. The Thermal Plot dialog box opens.

3

From the Units menu under the Properties tab, select SI.

4

Click the Display tab and select Section in the Plot Type box.

5

From the Component menu, select HFLUXN: Resultant heat flux .

6

Click the Settings tab and select None from the Boundary Options list.

7

Click OK.


7-23


8


To view the section plot properly, click *Right from the Orientation box.

Create Another Thermal Study on the Whole Assembly Now that we performed thermal analysis on the pipe without fin, the next step is to investigate the effect of the fin on the steady state temperature distribution. To save the pipe part and rebuild the assembly: 1

Save the Pipe part by clicking File, Save.

2

Close the Pipe part by clicking File, Close. You will get the following message,

3

Click Yes.

To create a thermal study on the assembly: 1


2

Create a thermal study with the name With Fin.

To assign material to the fin component: Assign Alloy Steel to the Pipe part and Aluminum Alloys (2024 Alloy) to the Fin part.

7-24

Apply Thermal Loads and Boundary Conditions We will apply the following thermal loads and boundary conditions:

q q

A temperature boundary condition on the inner face of the pipe in exact the same way we did in the No Fin study (i.e., with Ts=180 oC). Convection boundary conditions to the outer faces of the assembly (5 faces) with an overall heat transfer coefficient of 50 W/m2 oC.

To apply convection boundary conditions to the outer faces of the assembly: 1

Select the outer faces of the assembly. This time the faces of the fin should be included in the selection.

2

Right-click the Load/Restraint icon and select Convection.

3

In the Convection dialog box, select SI from the Units menu.

4

Enter 50 as the value of the Film Coefficient and 298 for the Bulk Temperature.

5

Click OK.

Selection for the convection boundary conditions in the Fin study

Mesh the Model Mesh the assembly with an element size of 0.11212 cm. This is the same element size we used to mesh the pipe component in the previous study. Also we will use the same meshing preferences. With this choice we can establish a basis for comparison of the results from the two studies.

Run Thermal Analysis on the Study Right-click the icon of the study and select Run.

Visualize the Resultant Heat Flux Plots To plot a section view of the resultant heat flux distribution: 1

Click the plus sign to the left of the Thermal folder under the Fin study.

2

Right-click Plot1 icon and select Edit Definition. The Thermal Plot dialog box opens.


7-25

3

From the Units menu under the Properties tab, select SI.

4

Click the Display tab and select Section in the Plot Type box.

5

In the Component list box, select HFLUXN: Resultant heat flux.

6

Click the Settings tab and select None from the Boundary Options list.

7

Click OK.

8

To view the section plot properly, click *Right from the Orientation box.

Conclusion By looking at the resultant heat flux values on the outer faces of the model for both cases (with and without fin), one can realize the effectiveness of the fin in dissipating heat out of the model. By closer investigation of the values of the resultant heat flux at the common face of the fin and the pipe, one can easily realized that the fin has enhanced the heat transfer rate by over an order of magnitude.

7-26


8 Optimization Analysis Tutorial

This chapter presents step-by-step lessons for performing optimization analysis.

q

Lesson 22: Shape Optimization of a Cantilever Bracket

q

Lesson 23: Shape Optimization of a Cylinder Assembly


8-1

Chapter 8 Optimization Analysis Tutorial

n Lesson 22: Shape Optimization of a Cantilever Bracket

Lesson 22: Shape Optimization of a Cantilever Bracket In this lesson you will learn how to:

q q q

Create an optimization analysis study, Define the objective function, design variables, and behavior constraints, and Visualize the results of the optimization process.

Introduction The purpose of this lesson is to show you how to perform optimization analysis on a given part. The fundamental ingredients of an optimization analysis study are: an objective function, design variables, and behavior constraints. The objective function usually defines the goal of the optimization process. In this release, you can set the objective function to minimize/maximize the mass, volume, natural frequency, and buckling load factor of a given design. The design variables, on the other hand, are the changeable dimensions of the model that we are seeking to optimize. The constraints define the conditions that the optimized design must satisfy (please refer to Chapter 9 in the User’s Guide book for more details). In this lesson we will be seeking an optimum design of a cantilever bracket, subjected to structural loading and boundary conditions, that will minimize its volume. We will start the lesson by performing static analysis on the initial design, then we will create an optimization study, and perform the optimization analysis to find the optimum design of the part.

Description The initial design of the cantilever bracket has the following dimensions;

Fixed face

Normal pressure

DV1

The part is subjected to the following loading and restraints: • A normal pressure with the value of 5x106 N/m2 on the top horizontal face, and • The part is fixed on the vertical back face.

8-2

DV3

DV2

We are seeking an optimum design of this part that minimizes its volume. The von Mises stress resulting from the specified loading is not to exceed a certain value (3x108 N/m2). The design variables (DV1, DV2, and DV3 in the graph) are to be within some upper and lower bounds. The optimization problem that we are trying to solve in this lesson has the following elements: Objective Function Minimize the volume of the cantilever part subject to the specified loading and restraints. Design Variables The upper and lower bounds imposed on the design variables are: • Design Variable DV1 (in mm): 10 < DV1 < 25, • Design Variable DV2 (in mm): 10 < DV2 < 25, and • Design Variable DV3 (in mm): 20 < DV3 < 50. Constraints The von Mises stress on the optimum design is not to exceed 3x108 N/ m2, within 5% tolerance.

Load the Part To load the part: 1

Start SolidWorks.

2


3

Navigate to the folder ...\Examples\Optimi zation, where “...”

refers to the installation folder of COSMOS/Works. 4

Make sure that the Files of type field is set to Part Files (*.prt, *.sldprt).


8-3


5


Select the Cantilever_Bracket.SLDPRT file, and click Open.

Create an Initial Static Analysis Study We will perform static analysis on the initial design. To do so we start the COSMOS/Works Manager by clicking the COSMOS/Works Manager toggle icon . To define a static analysis study on the initial design: 1

In the COSMOS/Works Manager, right-click the Cantilever_Bracket icon and select Study.

2

In the Study dialog box, click Add. The Study Name dialog box opens.

3

In the New Study field, type in Initial Stress.

4

From the Analysis Type menu, select Static.

5

From the Mesh Type box, select Solid.

6


7

Click OK.

Define Material Properties To define material properties to the part: 1

Right-click the Canilever_Bracket icon in the Solids folder and select Apply/ Edit Material.

2

In the Material dialog box, select Alloy Steel from the Material Name list box.

3

Click OK.

Apply Loads and Restraints To fix the vertical face of the bracket:

8-4

1

Select the vertical face of the bracket.

2

Right-click the Load/Restraint folder, and select Restraints.

3


4

Click OK.

Apply normal pressure to this face

Fix this face

To apply normal uniform pressure to the upper horizontal face of the bracket: 1

Select the horizontal face of the bracket.

2

Right-click the Load/Restraint folder and select Pressure.

3

In the Pressure dialog box, select SI from the Units menu.

4

Enter a value of 5x106 in the Value field.

5

Make sure that Normal to selected face is selected.

6

Click OK.



2


3


4


5

Make sure the 4 Points is selected from the Jacobian Check menu.

6

Click OK.



2

Click OK to accept the default element size.

Run the Initial Analysis To run static analysis on the initial design: Right-click the Initial Stress study icon and select Run. When the analysis is completed, click OK to close the message window.


8-5



Visualize Stress Results To plot von Mises stress: 1

Click the plus sign next to the Stress folder.

2


Create an Optimization Study To create an optimization study:

8-6

1

In the COSMOS/Works Manager, right-click the Cantilever_Bracket icon and select Study.

2


3

In the New Study field, type Min Volume.

4

From the Analysis Type menu, select Optimization.

5


6

Click OK.

To view the properties of the optimization study: 1

Right-click the Min Volume study icon and select Properties. The Optimization dialog box opens.

2

The Maximum no. of design cycles is set to 20.

3

Click OK.

Define the Objective Function To define the objective function: 1

Right-click the Objective icon and select Edit/Define. The Objective dialog box opens.

2

Click Add. The Objective dialog box opens.

3

In the Design Goal box, make sure that Minimize is selected.

4

In the Response Quantity list box, select Volume.

5

In the Available Studies list box, make sure that Initial Stress is selected.

6

In the Convergence Tolerance field, enter 5.

7

Click OK. You will return to the first dialog box.

8

Click OK. ✍ Note the red checkmark that appears on the Objective icon indicating that this item has been defined.


8-7



Define the Design Variables Next, we will define the design variables that the program will adjust so that the final goal (minimizing the volume) is achieved. To make the selection of the design variables easy, right-click the Mesh icon and select Hide Mesh. To define the design variables of the study:

8-8

1

Right-click the Design Variables icon and select Edit/Define. The Design Variables dialog box opens.

2

In SolidWorks graphics area, select any dimension by clicking it once, for example, DV1 (=25 mm), and click Add. The corresponding Design Variable dialog box opens. This dialog box will help you assign upper and lower bounds of the selected design variable.

3

In the Lower bound field, enter 10 (mm).

4

In the Upper bound field, enter 25 (mm).

5

In the Convergence tolerance field, accept the default value.

6

Click OK. The dimension will listed in the Design Variables dialog box.

7

To assign upper and lower bounds to the other dimensions (represented by DV2 and DV3), repeat steps (2-6).

8

Click OK to close the Design Variables dialog box.

Define Behavior Constraints As we mentioned earlier, we will require that the maximum von Mises stress on the optimized design to be less than 3x108 N/m2 within 5% tolerance. To define a study constraint: 1

Right-click the Constraints icon and select Edit/Define. The Constraints dialog box opens.

2

Click Add. The Constraint dialog box opens.

3

In the Response Type box, make the following selections; Static, Initial Stress, Nodal Stress, and VON: von Mises stress.

4

From the Units menu, select N/m2.

5

In the Bounds box, enter the following numerical values in the specified fields • Lower bound: 0, • Upper bound: 3e8, and • Tolerance: 5.

6

Click OK. The specified constraint will be listed in the Constraints dialog box.

7

Click OK.


8-9



Run the Optimization Analysis To run the analysis: Right-click the Min Volume study icon and select Run. The analysis starts. As the analysis runs, you will see the design variables changing in each design cycle until they reach their optimum values calculated by the program. When the analysis is completed successfully, a Convergence Achieved message window appears. Click OK to close the message window.

Visualize the Results Upon a successful completion of the optimization analysis on your model, postprocessing folders are generated.

Final Design Design after iteration No. 5

Final Design

View the Initial and Final Designs To view the initial or final design: Click the plus sign next to the Design Cycle Result folder. 2 Double-click the Initial Design icon. The initial design will display. 3 Double-click the Final Design icon. The final design will display. 1

To view the design at a certain cycle:

8-10

1

Right-click the Design Cycle Result folder and select Define. The Design Cycle Result dialog box opens. This dialog box tells you the number of design cycles the program took to achieve convergence.

2

In the Iteration No. field, enter the desired number of iterations after which you want to see the status of your design variables, for example, 5.

3

Click OK.

Convergence of Graphs To plot the convergence of the design variables: 1

Right-click the Design History Graph folder and click Define. The Design History Graph dialog box opens.

2

From the Graph Parameters menu, select Design variables.

3

Move all design variables from the Available Data box to the Plot Data box by clicking the double-arrow button.

4

Check Normalized to initial value checkbox.

5

Click OK. The following convergence plot will be generated in a separate window.

To plot the convergence of other optimization parameters: 1


2

From the Graph Parameters menu, select the parameter you want to plot.

3

Move that data you want to plot from the Available Data box to the Plot Data box.

4

Click OK.


8-11



Local Trend Graphs To plot the objective function versus a design variable: 1

Right-click the Design Local Trend Graph icon and select Define. The Local Trend Graph dialog box opens.

2

In the X-Axis box, select a design variable, for example, D11@Sketch@Cantilever_Bracket.

8-12

3

In the Y-Axis box, select Objective.

4


5

Click OK.

To plot a constraint versus a design variable: 1 Right-click the Design Local Trend Graph icon and select Define. The Local Trend Graph dialog box opens. 2

In the X-Axis box, select a design variable, for example, D13@Sketch@Cantilever_Bracket.

3

In the Y-Axis box, select Constraint. The drop-down menu field changes to VON: von Mises stress.

4


5

Click OK.


8-13



Round Off the Final Design Dimensions and Rerun Your Analysis The final dimensions of your design may or may not have decimal figures. Typically, for fabrication purposes, these figures should be rounded off to the closest number that can be measured within the precision of the fabrication process. The changes in dimensions of the final design may lead to higher stresses than those calculated by the program. In order to make sure that your stress constraint is still satisfied on your final model, you need to rerun static analysis on the finalized design and check the values of stresses throughout your model.


8-14

Lesson 23: Shape Optimization of a Cylinder Assembly In this lesson you will learn how to:

q q q

Create an optimization analysis study, Define the objective function, design variables, and behavior constraints, and Visualize the results of the optimization process.

Introduction The purpose of this lesson is to show you how to perform optimization analysis on a given assembly subjected to constraints from multiple studies. In this lesson we will be seeking an optimum design of a cylinder, subjected to thermal and structural loading that minimizes its volume. We will start the lesson by performing thermal and static analyses on the initial design, then we will create an optimization study, and perform the optimization analysis to find the optimum design that satisfies the constraints set by the user.

Description The initial design of the cylinder has the following dimensions.

Heat Source at the bottom


8-15


n Lesson 23: Shape Optimization of a Cylinder Assembly

The cylinder assembly consists of two parts; a heat source which is a circular disk located at the bottom of the assembly, and a heat sink which constitutes the rest of the cylinder. The heat source is made of Aluminum Alloy, and the heat sink is made of a Alloy Steel. Due to the symmetry of the model, we will analyze only a quarter of it. The model is subjected to the thermal loads shown in figure. Convection and radiation boundary conditions on this face Convection boundary condition on these faces.

Symmetry boundary conditions on the faces of symmetry of the model.

Heat power to the heat source component

Convection boundary condition on the bottom face of the heat sink

Objective Function Minimize the volume of the cylinder assembly subjected to the specified loading and restraints. Design Variables The upper and lower bounds imposed on the design variables are: • The outer radius of the cylinder: 6 < R < 10 inches, • The thickness of the cylinder wall: 1.5 < T < 2 inches, and • The height of the cylinder: 8 < H < 10 inches. Constraints The following constraints are to be applied: • The temperature throughout the model is not to exceed 430 oK. • The von Mises stress on the model is not to exceed 8x108 Nm-2.

8-16

Open the Assembly To open the assembly: 1

Start SolidWorks.

2


3

Navigate to the folder ...\Examples\Optimization, where “...” refers to the installation folder of COSMOS/Works.

4

Make sure that the Files of type field is set to Assembly Files (*.asm, *.sldasm).

5

Select the Quarter_Cylinder.SLDASM file, and click Open.

Create a Steady State Thermal Study We will perform steady state thermal analysis on the initial design. To do so we start the COSMOS/Works Manager by clicking the COSMOS/Works Manager toggle icon . To define a steady state thermal study on the initial design: 1

In the COSMOS/Works Manager, right-click the Quarter_Cylinder icon and select Study.


8-17



2


3

In the New Study field, type in Thermal Study.

4


5

In the Mesh Type box select Solid.

6


7

Click OK.

Assign Material Properties We will assign an Aluminum Alloy to the heat source and Alloy Steel to the heat sink. To assign material properties to the heat source: 1

Right-click the Quarter_Heat_Source-1 icon in the Solids folder and select Apply/Edit Material. The Material dialog box opens.

2

From the Material Type menu, select Aluminum Alloys.

3

From the Material Name menu, select Aluminum Alloy (1060 alloy).

4

Click OK.

To assign material properties to the heat sink:

8-18

1

Right-click the Quarter_Heat_Sink-1 icon in the Solids folder and select Apply/ Edit Material. The Material dialog box opens.

2

From the Material Type menu, select Steel.

3

From the Material Name menu, select Alloy Steel.

4

Click OK.

Apply Thermal Loads To apply convection to the faces of the heat sink: 1

Select the inner, outer, top, and bottom faces of the heat sink (5 faces).

2

Right-click the Load/Restraint folder and select Convection.

3

In the Convection dialog box, select SI from the Units menu.

4


5


6

Click OK.

To apply thermal symmetry boundary conditions on the faces of symmetry of the model: 1

Select the faces of symmetry of the model (4 faces).

2

Right-click the Load/Restraint folder, and select Heat Flux.

3

In the Heat Flux dialog box, enter 0 in the Heat Flux field.

4

Click OK.

To apply radiation boundary condition to the outer face of the heat sink: 1

Rotate the model to the appropriate view and select the outer face of the model.

2

Right-click the Load/Restraint folder and select Radiation.

3

In the Radiation dialog box, select Kelvin from the Units menu.

4

In the Emissivity field, enter 0.9.

5

In the View Factor field, enter 1.


8-19



6

In the Ambient Temperature field, enter 310.

7

Click OK.

To apply heat power to the heat source part: 1

Select the heat source part by clicking the Quarter_Heat_Source-1 icon in the Solids folder. Make sure that the selected part is highlighted in the graphics area.

2

Right-click the Load/Restraint folder and select Heat Power. The Heat Power dialog box opens.

3

From the Units drop-down menu, make sure that SI is selected.

4

In the Heat Power field enter 300 (Watts).

5

Click OK. ✍ The program uses the heat power loading when applied to components as a uniformly distributed volumetric heat source.


In the COSMOS/Works Manager, right-click the Mesh icon and select Preferences. The Preferences dialog box opens.

2


3

In the Mesh Control box, check Smooth Surface checkbox.

4


5

From the Jacobian Check menu, make sure that 4 Points is selected.

6

Click OK.

To mesh the model:

8-20

1


2

In the Global Size field, enter 1 (in inches).

3

Click OK.

Run the Analysis To run thermal analysis on the initial design: Right-click the Thermal Study study icon and select Run. When the analysis is completed, click OK to close the message window.

Visualize Thermal Results To plot temperatures: 1

Click the plus sign next to the Thermal folder.

2


Create a Thermal Stress Study Next, we will create a static study and compute the stresses developed in the model due to both thermal and structural loadings. To create a thermal stress study: 1


2


3

In the New Study field, enter an name for your study, for example, Thermal Stress.

4

From the Analysis Type menu, select Static.

5

In the Mesh Type box select Solid.

6


7

Click OK.


8-21



To set the properties of the static study: 1

Right-click the Thermal Stress icon, and select Properties. The Static dialog box opens.

2

Check Include Thermal Effects checkbox.

3

In the Thermal Options box, select Temperatures from thermal study.

4

Make sure that Thermal Study is selected in the Thermal Study field.

5

In the Reference temperature at zero strain field, enter 300 (in Kelvins)

6

In the Solver box, select FFE.

7

Click OK.

Assign Material to the Model Drag the Solids folder from the Thermal Study and drop it onto the Thermal Stress study icon. - or 1 Right-click the Solids folder in the Thermal Study and select Copy. 2

Right-click the Thermal Stress study icon and select Paste.

Apply Structural Restraints We will apply symmetry boundary condition to the faces of symmetry (4 faces) of the model, and fix the bottom faces of model (2 faces). To go back to the shaded view of the model, right-click the Mesh icon and select Hide Mesh.

8-22

To restrain the left faces: 1

Switch to the FeatureManager and click Plane1 in its tree.

2

Switch back to the COSMOS/Works Manager.

3

Select the two faces on Plane1 as shown in the figure.

4


5

In the Type dialog box, check Use Reference Plane or Axis.

6

In the Displacement box, check Normal to plane and enter 0 in its field.

7

Click OK.

Restrain these two faces along Dir 1 of Plane1

To restrain the right faces: 1

Select the other two faces of symmetry as shown in the figure.

2


3

In the Type dialog box, check Use Reference Plane or Axis .

4

In the Displacement box, check Along Plane Dir 1 and enter 0 in its field.

5

Click OK.

To fix the bottom faces of the model: 1

Select the two faces at the bottom of the model.

2

Right-click the Load/Restraint folder, and click Restraints.

3

In the Restraints dialog box, check Fixed.

4

Click OK.

Run Static Analysis Right-click the Thermal Stress study icon and select Run. The analysis starts. When completed, click OK to close the message dialog box.


8-23



Visualize Thermal Stresses To plot von Mises stresses: 1

In the COSMOS/Works Manager, click the plus sign to the left of the Stress folder under the Thermal Stress study.

2

Right-click Plot1 icon and select Edit Definition. The Stress Plot dialog box opens.

3

Click the Settings tab and enter 1 in the Scale Factor field.

4

Click OK.

Now, we will perform optimization analysis on the model, to find the optimum design (dimensions) that will minimize its volume. We will apply constraints from both Thermal Study and Thermal Stress studies.

Create an Optimization Study To create an optimization study: 1


2


3

In the New Study field, type Optimization Study.

4

From the Analysis Type menu, select Optimization.

5


6

Click OK.

To set the properties of the optimization study:

8-24

1

Right-click the Optimization Study icon and select Properties. The Optimization dialog box opens.

2

Set the Maximum no. of design cycles to 20.

3

Click OK.

Define the Objective Function To define the objective function for the optimization study: 1

Right-click the Objective icon and select Edit/Define. The Objective dialog box opens.

2

Click Add. The Objective dialog box opens.

3

In the Design Goal box, make sure that Minimize is selected.

4

In the Response Quantity list box, select Volume.

5

In the Available Studies list box, select Thermal Stress study.

6

In the Convergence Tolerance field, enter 1.

7

Click OK. You will return to the Objectives dialog box.

8

Click OK.


8-25



Define Design Variables To define the design variables of the study: 1

Right-click the Mesh icon and select Hide Mesh. The model displays in the shaded view mode and its dimensions are visible and ready for user selection. ✍ Hiding the mesh (or the results) is necessary for the next step of defining the design variables of the study.

2

Right-click the Design Variables icon and select Edit/Define. The Design Variables dialog box opens.

3

To add a design variable to the study select, for example, the radius dimension (D2@Sketch1@Quarter_Heat_Sink.Part) and click the Add button in the Design Variables dialog box. The Design Variable dialog box opens.

4

In the Lower bound field, enter 6 (in).

5

In the Upper bound field, enter 10 (in).

6

In the Convergence tolerance field, enter 2.

7

Click OK. The dimension will listed in the Design Variables dialog box.

8

To assign upper and lower bounds to the other dimensions (the wall thickness and height), repeat steps (2-6) with the appropriate lower and upper bounds and tolerance (as shown in the figure).

9

Click OK to close the Design Variables dialog box.

Defining the lower and upper bounds of a design variable

8-26

List of all design variables defined in in the current study

Define Behavior Constraints To define a stress constraint: 1

Right-click the Constraints icon and select Edit/Define. The Constraints dialog box opens.

2


3

In the Response Type box, make the following selections; Static, Thermal Stress, Nodal Stress , and VON: von Mises stress.

4

From the Units menu, select N/m^2.

5

In the Bounds box, enter the following numerical values in the specified fields • Lower bound: 0, • Upper bound: 2e9, and • Tolerance: 2.

To define a temperature constraint: 1


2

In the Response Type box, make the following selections; Thermal, Thermal Study, Thermal, and TEMP: Nodal temperature.

3

From the Units menu, select Kelvin.

4

In the Bounds box, enter the following numerical values in the specified fields • Lower bound: 0, • Upper bound: 430, and • Tolerance: 2.

5

Click OK. The specified constraint will be listed in the Constraints dialog box.

6

Click OK to close the Constraints dialog box.


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Run the Optimization Analysis To run the analysis: Right-click the Optimization Study icon and select Run. The analysis starts. As the analysis runs, you will see the dimensions specified as design variables changing in each design cycle until they reach their optimum values calculated by the program. When the analysis is completed successfully, a Convergence Achieved message window appears. Click OK to close the message window.

Visualize the Results View the Initial and Final Designs To view the initial or final design: 1

Click the plus sign next to the Design Cycle Result folder.

2

Double-click the Initial Design icon. The initial design will be displayed.

3

Initial Design

Double-click the Final Design icon. The final design will be displayed.

To view the design at a certain cycle: 1

Right-click the Design Cycle Result folder and select Define. The Design Cycle Result dialog box opens. It displays the number of iterations needed to achieve the optimum design.

2

In the Iteration No. field, enter the desired one, for example, 4.

3

Click OK.

Final Design

Design variables after 4 iterations

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Convergence Graphs To plot the default design variable convergence graph: 1

Click the plus sign to the left of the Design History Graph folder.

2


To plot the convergence of all design variables: 1


2

From the Graph Parameters menu, select Design variables.

3

Move all design variables from the Available Data box to the Plot Data box by clicking the double arrow button.

4

Click OK. The following convergence plot will be generated in a separate window.


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Local Trend Graphs To plot the objective function versus the first design variable: 1

Click the plus sign to the left of the Design local Trend Graph folder.

2


✍ You can generate other graphs by right-clicking the Design Local Trend Graph folder and selecting Define.


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Cosmos Works Tutorials

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