Intermediate-Finite-Element-Analysis-with-Open-Source-Software.pdf

e t Finite Fin ite Eleme El emen n t Analysis Anal ysis u sing a i d e m r Open source Software In te n Moment on Nozzle

Natural frequency

Non-linear Contact

Thermal

- by Dharm Dharmit it A. Tha Thakore kore

Intermediate Finite Element Analysis with Open Source Software First Fir st Edition Ed ition

Intermediate Finite Element Analysis with Open Source S ource Sofware Sofware First Edition

Dharmit Takore, CPEng, RPEQ Moonish Ent. Pty. Ltd. Brisbane, QLD, Australia

Moonish Enterprises Pty Ltd GPO Box 1299, Brisbane, QLD 4001, Australia 2014

Credits and Copyright Written by: Dharmit Takore [email protected]

Publisher: Moonish Ent. Pty. Ltd [email protected] http://engineering.moonish.biz

Graphic Design / Layout: Lomesha Takore [email protected]

Edition 1 ©2014 Dharmit Takore

No part o this publication may be reproduced, stored or transmitted in any orm or by any means, electronic, mechanical or otherwise, without prior written consent rom the publisher, except or the inclusion o brie quotations in a review. You may store the pd on your computer and backups. You may print one copy o this book or your own personal use. Disclaimer: Te inormation contained in this book is based on the author’s experience, knowledge and opinions. Te author and publisher will not be held liable or the use or misuse o the inormation in this book.

o My wie, Our beloved son & Open Source Sofware

About the Author Dharmit Takore is the Director o Moonish Enterprises Pty Ltd at Brisbane, Queensland, Australia. He practices as a Mechanical / Piping Engineer in Queensland. He received his Bachelor’s degree rom Birla Vishwakarma Mahavidhyalaya, Vallabh Vidhyanagar, Gujarat, India which was affiliated with Sardar Patel University. He started his engineering career as a young Graduate in Larsen & oubro – Sargent & Lundy, Vadodara. He came to Australia or urther studies and settled here. He received his Registered Proessional Engineer in Queensland (RPEQ) recognition early in his career and subsequently obtained his Chartered Proessional Engineer (CPEng) as a Mechanical / Piping Engineer. Dharmit has broad interests, which include finite element analysis, design, optimization and Open Source sofware. He is a member o ASME, Engineers Australia and Board o Proessional Engineers in Queensland.

able o Contents Foreword Tis book is written or Tis book is not written or

What are the steps in Finite Element Analysis Study Cases Parametric Modelling in Salome or Geometry and Mesh generation Combining element types in a single FE Analysis Non Linear Material Analysis Contact FE analysis Modal Analysis Termal Analysis

Parametric Modelling o a Pressure Vessel Geometry Step 1: Description o the problem Step 2: Input values or the FE analysis Step 3: Parametric Modelling by direct editing o .py file Step 4: Meshing using Notebook Change Parameter in Notebook Summary

Adding Moments to a ace in 3D model Step 1: Description o the problem Step 2: Input values or the FE analysis Step 3 and 4: Generating Geometry by Parametric Modelling and editing mesh Step 5, 6, 7, 8 and 9: Reusing .comm file rom Case9 and editing it Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Combining Element types in a single FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Generating command file by hand Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear Material FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry

xiii xiii xiii

xv xvii xvii xvii xvii xvii xvii xviii

1 2 2 2 30 34 36

37 38 38 38 44 49 50 55

56 57 57 57 66 69 73 75 80

81 82 82 83 85

Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear Material – Real Curve FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear FE Analysis with Contact Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear FE Analysis with Contact and Non-Linear Material Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

FE Analysis o 3D Plate or Mode Shapes Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Creating command file by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

FE Analysis o 1D Beam or Mode Shapes

88 96 102 106

108 109 109 110 110 110 114 114 116

117 118 118 119 123 126 134 139 142

143 144 144 145 145 145 148 149 150

151 152 152 154 156 159 162 162 167

168

Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

FE Analysis o 2D Plate or Mode Shapes Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Termal Conduction FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Creating command file by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Termal Convection FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Creating command file by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

What will be covered in Volume 3 Using Python or Parametric Modelling and FE Analysis Using Hommard or adaptive meshing Advanced Termal FE Analysis Termo-Mechanical FE Analysis Pipe Stress Analysis

169 169 171 173 175 178 178 183

184 185 185 186 188 190 192 195 199

200 201 201 202 203 206 209 210 213

214 215 215 216 222 225 227 227 229

230 230 230 230 230 230

Fluid Structure Integration

Appendix A Other sources o inormation

Appendix B Installing Sofware required or this book Ubuntu 12.04 Configuration Salome-Meca 2013.2 installation Efficient Install

231

232 232

233 233 233 234 236

Foreword

Foreword Afer the success I received by writing my first Book “Finite Element Analysis using Open Source Sofware”, I received many email communications congratulating me and telling me how easy it was to use my book. Readers had ound an easy to use, easy to read and easy to ollow documentation or Open Source Sofware that can be used or Finite Element analysis. Some said that they completed the entire book with the exercise within one single weekend and I doubt i they had taken any sleep in between. Te users o my book were resh graduates rom the university who knew the undamentals and had been using proprietor sofware in their university and now as they were out o university, they wanted to use something that doesn’t hurt their hip pocket. Others were seasoned proessionals who knew other proprietary sofware but wanted to know how to perorm FEA using Open Source Sofware. Tis book starts with updated examples in version 11.x or Code_Aster rom previous book. It then goes on and adds on advanced analysis.

Tis book is written or Tose who have a passion or learning Open Source sofware, particularly CAD and FEA sofware. Tis book is written or those who are new to sofware like Salome and Code_Aster. I you are having trouble understanding where to start with Salome and Code_Aster, this book is written or you. I you are having troubles understanding the computer translated Code_Aster User Documents (which are rich in inormation), this book is written or you. I you want easy reerence to 75% o FEA problems that are encountered by engineers in day to day lie and want to do that by Open Source Sofware, this book is written or you. Tis book is or those who don’t want to waste their time in finding tutorials online and trying to make logical and sequential sense. Tis book starts with a very basic introduction o what to do to perorm FE Analysis, and then, with each new Chapter, it introduces new concepts in an easy to understand ormat. I you want to learn how to do FE Analysis with Open Source sofware in a week’s time, than this book is or you.

Tis book is not written or I you are advanced user o Salome and Code_Aster and afer reading the able o Content you can say to yoursel that “the inormation covered in this book is something that I already know”, this book is not or you. Tis book is also not written or someone who does not know what Finite Element Analysis is. FE Analysis, as a undamental, should be known to the user o this book. I you are a beginner, it is advised that you purchase our first book “Finite Element Analysis with Open Source Sofware” where you will be able to gain more insights into the undamental analysis that can be done with SalomeMeca and Code_Aster. Once you are amiliar with those concepts, this book will be easy to ollow. Some o the chapters in this book rely on the inormation given in the first book. Tough it is not necessary, it is recommended to complete the first book beore you start with this one.

— xiii —

Finite Element Analysis using Open Source Software

What sofware would you need to ollow through Operating System used: 1. Ubuntu 12.04 Sofware used or this book are 1. Salome-Meca version 2013.2 2. Code Aster version 11.3 3. Efficient version 0.1.1 All o the above sofware (except latest version o Efficient) are available in CAELinux 2013 DVD so i you have installed it, don’t worry about any more installations. I you want to use latest sofware, install the above versions or latest versions o these sofware on your computer. Please note that i you install a sofware that is o higher version than that mentioned above, the screenshots may differ, but the undamental concepts remain the same.

— xiv —

What are the steps in Finite Element Analysis

What are the steps in Finite Element Analysis Tis book does not teach you what Finite Element Analysis is. You are nearly ready i you are amiliar with the general orm o Hook’s law which states that “For small deormations o the object, the amount o deormation / displacement (Dx) is directly proportional to the deorming orce or load (F)”. Te constant o proportionality in the above equation is the stiffness (k) o the object. Generally the stiffness o the object is known due to the act that we would have its shape and material properties as a given. I not, Either we would be optimising its shape by finding stresses generated in the object due to applied loads (e.g. objective o the study can be “optimise web thickness o gussets or optimise thickness o a pressure vessel Nozzle saddle”), or we would be checking which material is most suitable or the given object (e.g. objective o the study can be “Can Aluminium alloy be used to reduce the weight o the object?”). So stiffness “k” would be fixed or the given analysis based on shape and material selected. Te next step is boundary conditions. Any given object has to be sufficiently supported in the real world and FEA will emulate these supports, either there is a fixed support (e.g. bolted or welded joint), sliding support (e.g. shaf in hub or pipe shoe on structural steel). By applying these boundary conditions o supports, we are providing / fixing values o displacement. Ten there would be orces applied to the object, either by gravity (sel-weight) or by pressure applied on a surace or orce applied on the object. By adding these boundary conditions o loads, we are providing / fixing values o orce / load. Afer all o the above is given to Code Aster (FE analysis sofware o choice or this book), it tries to solve the equation which will be in matrix orm with the given input values o displacement and orces and obtain displacement or the entire object. Tese displacements (Strains) are converted to Stresses (Stress = Strain multiplied by Young’s Modulus o the material, or elastic case) and are displayed as a coloured model or exported as a table. Figure on the next page shows general steps to perorm FEA.

— xv —


In the coming chapters o this book, we will be using above philosophy to carry out Finite Element Analysis. Interpretation o results will be lef to the reader.

— xvi —

Study Cases

Study Cases Afer Esha learnt how to perorm FEA using Open Source Sofware like Salome-Meca and Code_Aster, she started her proessional career in the same firm that she did her internship. She was happy that John was her mentor all the way long. Esha started gaining more experienc experiencee with Linear Static Finite Element Analysis, and with more experience she needed less reliance on John’ John’s guidance. Esha started doing her FE Analysis with more confidence. Afer several months, John caught up with Esha to find out how she was eeling regarding the use o Open Source Sofware or Finite Element Analysis. Esha was very excited to tell John all about her experience experiencess while they met or coffee. Ten Esha told John that every now and then a different type o FE Analysis comes to her or which she is not ready yet. She has to pass them to her other colleagues as she sh e is not eeling confident and she is eeling a bit lost. As usual John was listening to her words careully and asked her i he could help. Esha was waiting or John John to say that and she listed the analysis which she elt were a bit tough or her to do.

Parametric Modelling in Salome or Geometry and Mesh generation Esha said that John had taught her how to “Dump the study” so that i she wants to recreate the geometry and mesh, it becomes easy or her. But what i she wants to change some o the parameters. What i Esha wants to generate geometry o the Pressure Vessel and Nozzle junction with different PV Diameter and Nozzle Diameter? What i she wants to change the mesh density in the PV Shell thickness or in the Nozzle thickness?

Combining element types in a single FE Analysis Esha said that sometimes the models are too big and it would really help her i she could combine 3D elements with shell elements and Beam elements. Tis would make FE Analysis run aster without compromising her results. Was there a way to do this in Salome and Code_Aster?

Non Linear Linear Material Material Analysis Analysis Esha said that what John taught her in last book in Chapter 9 or checking against Allowable stress o the material was sufficient at that time, but she wanted to know i she could put the Graph o the Material Properties in Salome or Code-Aster and i the Analysis could take care o checking when the Allowable stress has been reached and stop the analysis?

Contact FE analysis Esha said that she was happy to perorm Assembly FE Analysis, but sometimes there is a requirement where she needs a gap between two parts and that load can only be translated once there is contact between suraces. sur aces. Was there a way to do it in Code_Aster?

Modal Ana Analysis lysis Sometimes in her career, Esha had come across a FE problem where she needed to find the Natural requencies o a given shape o the object. Esha asked John, i it was possible in Code Aster to find out the Natural requencies o

— xvii —


the object by perorming Modal Analysis?

Termal Analysis Esha remembered that once she was asked i there was a way to perorm Termal analysis in Code_Aster. As Esha didn’t didn’t know, know, she had to again pass it along to her colleague. Is there a way to conduct Termal Analysis in Code_Aster? Tese were some o the example problems that she had the opportunity to do but was not able to do them due to her limited knowledge. Tere were some more more problems that she wanted to discuss with John but first she wanted to know i her existing problems can be solved. John told Esha that both Salome and Code_Aster were capable o conducting the analysis she asked or and much more.

— xviii —

Parametric Modelling of a Pressure Vessel Geometry

Chapter 1 - Case12 Parametric Modelling o a Pressure Vessel Geometry John was glad that Esha asked or help when she needed. John said that first he will show Esha, how to perorm a Parametric Modelling o the same Pressure Vessel Geometry that they created in Chapter 9 / Case 9 o previous book. Tis time Esha was the client as she had a specific request and John was the Engineer.

—1—

Intermediate Finite Element Analysis using Open Source Software

Step 1: Description o the problem John asked Esha, what the exact outcome that Esha was looking or was. Esha said that in previous book in Chapter 9 John had showed her how to save a Python file rom which she could generate the geometry again and again. But editing that file was time consuming and sometimes she made a mistake in entering the data and was conused in looking through throug h series o lines o Python in the “.py” “.py” file. She wanted to know i there was an easy way in which she could just enter the values o the Parameters and Salome could do the modelling and meshing by itsel. John said that Salome indeed was very powerul and the request that Esha made was easily achievable in Salome. John told Esha that there are are two methods in which the request that Esha has made can be accomplished. One method is to edit the “.py” file manually, enter additional parameters and use them in the file to generate geometry and mesh it. Te second method was to use something called call ed “Notebook” “Notebook” in Salome that stores parameters and which can be edited. edited. John will show Esha both o this methods. methods.

Step 2: Input values or the FE analysis Dimensions o the Pressure Vessel are similar to the previous book Chapter 9. ID o Cylindrical shell o PV: 2000mm (2m) Tickness o Cylindrical shell o PV: 10mm (0.01m) Hal Length o Cylindrical shell o PV: 1500mm (1.5m) Dimensions o the Nozzle are ID o the Nozzle: 300mm (0.3m) Tickness o the Nozzle: 10mm (0.01m) Projection o Nozzle: 300mm (0.3m)

Step 3: Parametric Modelling by direct editing o .py file John copied Python file “Case9.py” rom Case9 older and saved it as “Case12.py” in a separate older named Case12. Ten John double clicked the file to open it. He told Esha that each and every line in this file is either a code that tells Salome about the geometry geometry and mesh or is a comment. Ten he scrolled down the file till he could see the ollowing code. # -*- coding: iso-8859-1 -*-

###

### This le is generated automatically by SALOME v6.3.0 with dump python functionality ###

—2—


Just below the above statements we will write our code or making this file do parametric modelling. Tis code

can be written anywhere in the file, but as these lines o code are or initialising variables that store inormation the will be used in modelling they should be initialised beore the values are used. Python code is really easy and i you have done programming with any other language, you will eel Python to be a un and easy language. Tings to remember in Python language: 1. You don’t need to end the statement with a semi-colon “;” 2. Python ends the statement when “Enter” (Carriage Return / Line Feed) is encountered 3. I you are initialising a variable, Variable Name will be on the lef side o the = sign and value will be on the right side 4. Mathematical operations have regular meaning and precedence 5. Everything afer “#” will be considered as a comment With this in mind let’s add variables that will hold inormation or Geometry and Mesh. Add the ollowing lines: #########################

#Parameters for Geometry# #########################

#Pressure Vessel Outside Radius PV_OR = 1010 #Pressure Vessel Inside Radius PV_IR = 1000 #Pressure Vessel Height PV_Height = 1500 #Nozzle Outside Radius Nozz_OR = 160 #Nozzle Inside Radius Nozz_IR = 150 #Nozzle Protrusion Length Nozz_Protrusion = 200 #Height of Cylinder for Nozzle Construction Nozz_Len = PV_OR + Nozz_Protrusion

—3—


#####################

#Parameters for Mesh# #####################

#Number of Segments for Global Meshing GlobalSeg = 15 #Number of Segments for Pressure Vessel Shell Thickness Meshing PVSeg = 5 #Number of Segments for Nozzle Shell Thickness Meshing NozSeg = 5 ###################

#End of Parameters# ###################

Afer adding the parameters that will be used in the creation o geometry and mesh, lets add these in the python file. Find the lines shown below and enter the parameters defined earlier in their respective locations. Parameters entered manually are shown with Red colour. Cyl_PV_OD = geompy.MakeCylinderRH(PV_OR, PV_Height) Cyl_PV_ID = geompy.MakeCylinderRH(PV_IR, PV_Height) Cyl_Noz_OD = geompy.MakeCylinderRH(Nozz_OR, Nozz_Len) Cyl_Noz_ID = geompy.MakeCylinderRH(Nozz_IR, Nozz_Len) Vx = geompy.MakeVectorDXDYDZ(1, 0, 0) Vy = geompy.MakeVectorDXDYDZ(0, 1, 0) Vz = geompy.MakeVectorDXDYDZ(0, 0, 1) geompy.Rotate(Cyl_Noz_OD, Vy, 90*math.pi/180.0) geompy.Rotate(Cyl_Noz_ID, Vy, 90*math.pi/180.0) geompy.TranslateDXDYDZ(Cyl_Noz_OD, 0, 0, PV_Height / 2) geompy.TranslateDXDYDZ(Cyl_Noz_ID, 0, 0, PV_Height / 2) Geom_OD = geompy.MakeFuse(Cyl_PV_OD, Cyl_Noz_OD) Geom_ID = geompy.MakeFuse(Cyl_PV_ID, Cyl_Noz_ID) PV_Whole = geompy.MakeCut(Geom_OD, Geom_ID) #Please note that § is entered here for clarity purpose # to show that line continues below without any break

—4—


# Please do NOT enter § sign in your code. a3D_Sketcher_1 = geompy.Make3DSketcher([0, 0, 0, PV_OR, PV_OR, 0, § PV_OR, PV_OR,PV_Height, 0, 0, PV_Height, 0, 0, 0]) Face_1 = geompy.MakeFaceWires([a3D_Sketcher_1], 1) Revolution_1 = geompy.MakeRevolution(Face_1, Vz, 270*math.pi/180.0) PV = geompy.MakeCut(PV_Whole, Revolution_1) P0 = geompy.MakeVertex(0, 0, PV_Height / 2) Plane_Vy = geompy.MakePlane(P0, Vy, PV_OR * 5) Plane_Vz = geompy.MakePlane(P0, Vz, PV_OR * 5) PV_1 = geompy.MakePartition([PV], [Plane_Vy, Plane_Vz], [], [], § geompy.ShapeType[“SOLID”], 0, [], 0) P1 = geompy.MakeVertex(0, 0, 0) P2 = geompy.MakeVertex(0, (PV_OR * math.sin(45*math.pi/180.0) + § Nozz_OR) / 2, PV_Height / 2) P3 = geompy.MakeVertex(0, 0, PV_Height)

By doing above changes we have made geometry creation parametric. Now to make meshing parametric, find the lines shown below and then we need to make ollowing changes Global_Mesh_Seg = Regular_1D.NumberOfSegments(GlobalSeg) Global_Mesh_Seg.SetDistrType( 0 ) Quadrangle_2D = PV_Mesh.Quadrangle() Hexa_3D = smesh.CreateHypothesis(‘Hexa_3D’) status = PV_Mesh.AddHypothesis(Hexa_3D) Regular_1D_1 = PV_Mesh.Segment(geom=PV_SubMsh) PV_Thk_Seg = Regular_1D_1.NumberOfSegments(PVSeg) PV_Thk_Seg.SetDistrType( 0 ) Propagation_of_1D_Hyp_on_opposite_edges_1 =

§

Regular_1D_1.Propagation() Regular_1D_2 = PV_Mesh.Segment(geom=Noz_SubMsh) Noz_Thk_Seg = Regular_1D_2.NumberOfSegments(NozSeg)

By doing above changes we have made the meshing as parametric too.

—5—


Now Start Salome Meca and Click File -> Load Script, then select the python file we saved earlier, afer some time mesh o the Pressure vessel with the dimensions you entered in parameters will be displayed. Just to check i the python file and parameters are working properly, John entered ollowing parameters (Changes marked in Red) #########################


#Pressure Vessel Outside Radius PV_OR = 1050 #Pressure Vessel Inside Radius PV_IR = 1000 #Pressure Vessel Height PV_Height = 1500 #Nozzle Outside Radius Nozz_OR = 300 #Nozzle Inside Radius Nozz_IR = 290 #Nozzle Protrusion Length Nozz_Protrusion = 200 #Height of Cylinder for Nozzle Construction Nozz_Len = PV_OR + Nozz_Protrusion #####################


#Number of Segments for Global Meshing GlobalSeg = 15 #Number of Segments for Pressure Vessel Shell Thickness Meshing PVSeg = 5 #Number of Segments for Nozzle Shell Thickness Meshing NozSeg = 5 #End of Parameters# ###################

—6—


And he got ollowing as a result

As can be seen, the thickness o Pressure vessel has increased and the Nozzle diameter has also increased.

—7—


Step 3 again: Parametric Modelling by using Notebook John told Esha that Salome provides a eature called Notebook which is very powerul and that is what we are going to use next. #

Description

Figure

1

Modelling steps shown here are exactly same as shown in previous book in Chapter 9, with the only difference o using Notebook to add parameters. First we will add Parameters to the Notebook and then use those while generating geometry and mesh. Open Salome-Meca and start Geometry Module.

Click File -> Notebook and a window will popup as shown in adjacent figure. 2 Tis is Salome Notebook. It is blank right now, but we will add Parameters 1 soon.

Click below Variable Name and the field will be ready to accept Variable Name.

3

Enter “PV_OR” as the variable name, Press “ab” and the ocus will move to Variable Value, enter “1010” as the Variable Value. PV_OR is Outside Radius o Pressure Vessel with a value o 1010mm.

—8—


#

Description

Figure

Enter other parameters as shown in adjacent figure. 4

One thing to note here is the “Nozz_Len” which is given a Variable Value as addition o a two Variables.2

We are done adding Geometric Parameters. Click “Apply and Close” 5 Next we will start generating our geometry.

—9—


#

Description

Figure

Click New Entity -> Primitives -> Cylinder. Select the second Option or cylinder, give it a Name “Cyl_ PV_OD” and enter “PV_OR” or Radius and “PV_Height” or Height. Click “Apply”

6

For second Cylinder, use “Cyl_ PV_ID” as Name and enter “PV_IR” or Radius and “PV_ Height” or Height. Click “Apply” Use “Cyl_Noz_OD” as Name and enter “Nozz_OR” or Radius and “Nozz_Len” or Height. Click “Apply” Use “Cyl_Noz_ID” as Name and enter “Nozz_IR” or Radius and “Nozz_Len” or Height. Click “Apply and Close” As can be seen rom the Cylinders that have been created, we need to ranslate and Rotate the cylinders created or Nozzle and place them in their proper location and orientation.

7 For that we need to create Vectors in all three directions. Ten use Vector in Y direction to rotate the cylinders or nozzle and then translate them.

— 10 —


#

Description

Figure

Click New Entity -> Basic -> Vector. Select the Second Option or Vector, Give it a name “Vx” (Vector in X direction) and enter 1, 0, 0 or X, Y and Z. 8

Click “Apply” Next give the name “Vy” and enter 0, 1, 0 or X, Y and Z. Click “Apply” Next give the name “Vz” and enter 0, 0, 1 or X, Y and Z. Click “Apply and Close”

Click Operations -> ransormation -> Rotation.

9

Select “Cyl_Noz_OD” as Objects, “Vy” as Axis, enter “90” as Angle and Untick “Create a copy” as we do not want to create a new cylinder. Click “Apply” In the similar manner, Rotate “Cyl_Noz_ID” as shown above as well. Click “Apply and Close”

— 11 —


#

Description

Figure

10

Next to transorm the Cylinders we need Hal height o the Pressure Vessel, As we did not create it earlier, we need to create it now. Note that Salome does not allow Arithmetic operations in the field where you need to enter Values. You can only perorm arithmetic operations in Notebook.

Click File -> Notebook and add “PV_Hal_Height” as a new Variable as shown in adjacent figure. 11

Click “Apply and Close”. As you can see, i you orgot to add a Variable at the start o the geometry creation, you can do that at a later stage.

— 12 —


#

Description

Figure

Click Operations -> ransormation -> ranslation.

12

Select “Cyl_Noz_OD” as Objects, and enter “PV_Hal_ Height” or Dz, Untick “Create a copy” as we do not want a new copy o translated cylinder. Click “Apply”. ranslate “Cyl_Noz_ID” shown above as well.

as

Click “Apply and Close”.

Now we need to use the Pressure Vessel and Nozzle OD Cylinders to generate a Geometry or the OD and then we need to use ID Cylinders to generate a Geometry or ID. 13 Afer that we need to Remove the ID geometry rom OD geometry to generate a Geometry that will be our Pressure Vessel.

— 13 —


#

Description

Figure

Click Operations -> Boolean -> Fuse. Give it a Name “Geom_OD” and select “Cyl_PV_OD” as Object 1 and “Cyl_Noz_OD” as Object 2. 14

Click “Apply” Enter a new Name “Geom_ID” and select “Cyl_PV_ID” as Object 1 and “Cyl_Noz_ID” as Object 2. Click “Apply and Close”

Click Operations -> Boolean -> Cut. 15

Give it a Name “PV_Whole” and select “Geom_OD” as Main Object and “Geom_ID” as ool Object. Click “Apply and Close”

— 14 —


#

Description

Figure

Right Click “PV_Whole” in Object Browser and Select Show Only. Change the mode to “Shading”.

16

You should be able to see something similar to adjacent figure. Rotate it, zoom it and see the Pressure Vessel shell that you have created. Next we will remove excess geometry as we only need 90 degrees o this whole PV.

— 15 —


#

Description

Figure

Click New Entity -> 3D Sketch. In the window that opens, keep deault name and “Absolute” Coordinates ype. Enter ollowing Numbers or X, Y and Z respectively: 0, 0, 0 -> “Apply” 17

PV_OR, PV_OR, 0 -> “Apply” PV_OR, PV_OR, PV_Height -> “Apply” 0, 0, PV_Height -> “Apply” Next, Click “Sketch Closure”. Tis will create a rame or the ace we will create in next step.

Now we need to create a Face out o the 3D sketch we just created. Click New Entity -> Build -> Face. 18

Keep deault Name “Face_1”, select “3D Sketcher_1” as Objects and make sure that “ry to create a planar ace” is ticked. Click “Apply and Close”

— 16 —


#

Description

Figure

Now we will revolve this ace to create the geometry. Click New Entity -> Generation -> Revolution. 19

Keep deault Name as “Revolution_1”, Select “Face_1” or Objects and “Vz” or Axis. Enter “270” or Angle, Untick “Both Directions”. Click “Apply and Close”

Click Operations -> Boolean -> Cut. 20

Give it a Name “PV” and select “PV_Whole” as Main Object and “Revolution_1” as ool Object. Click “Apply and Close”

— 17 —


#

Description

21

Right Click “PV_Whole” in Object Browser and Select Show Only. Change the mode to “Shading”.

Figure

You should be able to see something similar to adjacent figure.

We will need to partition this geometry such that each partitioned solid has only 6 edges. 22

We need to create two planes that will cut the Geometry in 4 equal pieces. For this we will need to create two planes perpendicular to each other and that intersect at the centre o the nozzle.

— 18 —


#

Description

Figure

First we will create a point rom which the plane will pass. Click New Entity -> Basic -> Point. 23

Click on First constructor o Points, give it a Name “P0” and enter co-ordinates as shown in the adjacent figure. Click “Apply and Close”

24

Now we need to create two Planes with sizes equal to 5 times the Diameter o Pressure Vessel. So we will go back to Notebook and add another Parameter “OR_x_5” as shown in adjacent figure

— 19 —


#

Description

Figure

Click New Entity -> Basic -> Plane.

25

In the window, Select first constructor or Plane, give it a Name “Plane_Vy”, Select “P0” as Point and “Vy” as Vector. Enter “OR_x_5” as the “Size o plane”. Click “Apply” For the second Plane, give it a Name “Plane_Vz”, Select “P0” as Point and “Vz” as Vector. Enter “OR_x_5” as the “Size o plane”. Click “Apply and Close”

Now we partition the geometry. Click Operations -> Partition.

26

Give it a Name “PV_1”, select “PV” as Objects and or the ool Objects select both Planes “Plane_Vy” and “Plane_Vz” in the Object Browser by Clicking on them while pressing “Ctrl”. Make sure Resulting ype is “Solid”. Click “Apply and Close”

— 20 —


#

Description

Figure

We are not done yet, we still need to partition this geometry urther such that each individual solids will have only 6 sides. Next we will create a curve edge that will aid in generating a curved surace to partition the geometry urther. 27

At this point in time, Notebook is not able to handle advanced python code like the one we added manually in “Case12.py” (PV_OR * math.sin(45*math.pi/180.0) + Nozz_OR) / 2

so we will just add a simple ormula or Point P2 as PV_OR / 2.5

28

Add another variable named “Point_2_y” with the value as shown in adjacent figure

— 21 —


#

Description

Figure

Click New Entity -> Basic -> Point. Click on First constructor o Points, give it a Name “P1” and enter co-ordinates as shown below. 29

For Point “P1” enter 0, 0, 0 or X, Y, Z -> Click “Apply” For Point “P2” enter 0, Point_2_y, PV_Hal_Height or X, Y, Z -> Click “Apply” For Point “P3” enter 0, 0, PV_Height or X, Y, Z -> Click “Apply and Close”

Next we generate a Curve rom these three points. Click New Entity -> Basic -> Curve Select third constructor or Interpolation, keep deault Name o “Curve_1”, Creation Mode should be “By Selection”. 30

Now or Points we will directly select them rom Object Browser by Clicking on them while holding “Ctrl” key. Te order in which you select the points is critical as the interpolation will occur based on that selection. Select Point “P1” then “P2” and last “P3”. Click “Apply and Close”

— 22 —


#

Description

Figure

We will extrude this “Curve_1” to generate our curved plane. Click New Entity -> Generation -> Extrusion. 31

Select first constructor or Extrusion, keep deault Name o “Extrusion_1”, select “Curve_1” as Base and “Vx” as Vector, enter “Nozz_Len” or Height. Click “Apply and Close”

— 23 —


#

Description

Figure

Now we will mirror this Extrusion to orm our second ool object or Partition. Click Operations -> ransormation -> Mirror Image. 32

Select third constructor or Mirror, keep deault Name o “Mirror_1”, select “Extrusion_1” or Objects and “Plane_Vy” or Plane Mirror. Make sure “Create a copy” is ticked as we want a copy o the existing extrusion. Click “Apply and Close”

— 24 —


#

Description

Figure

Now we partition the geometry. Click Operations -> Partition.

33

Give it a Name “PV_2”, select “PV_1” as Objects and or the ool Objects select Planes “Extrusion_1” and “Mirror_1”. Make sure Resulting ype is “Solid”. Click “Apply and Close”

We still need more partitions to make sure that every ace has 4 edges and every solid has 6 aces. Right Click Cylinder “Cyl_PV_ OD” and Select “Show Only” Click New Entity -> Group -> Create. 34

Select third constructor or Shape ype, change the Name to “PV_OD”, the Main Shape should be “Cyl_PV_OD” and select the Cylindrical Surace and Click “Add” Click “Apply and Close” Next do the same or Cylinder “Cyl_Noz_OD” and give it a name “Noz_OD”.

— 25 —


#

Description

Figure

Now we partition the geometry one last time. Click Operations -> Partition.

35

Give it a Name “PV_Final”, select “PV_2” as Objects and or the ool Objects select Planes “PV_OD” and “Noz_ OD”. Make sure Resulting ype is “Solid”. Click “Apply and Close”. Right Click “PV_Final” and Select “Show Only” and you should be able to see something similar to the adjacent figure.

Now that the Geometry modelling is complete, we need to create Groups o Faces where we will apply Boundary Condition and Loads. 36 Boundary Conditions will remain same as Previous Study we did or Pressure Vessel Shell or most o the part.

— 26 —


#

Description

Figure

Click New Entity -> Create -> Group, Select the Tird button to Add Face.

37

Give Name “Dz0” to the bottom ace o the shell, “LongPres” to the top ace and “Norma” to the two vertical aces. Give Name “Press” to the Inside Face o the Pressure Vessel Shell and also to the Inside ace o Nozzle.

We will need a Face Group on the Nozzle to apply Force. 38

Give it a Name “Force” and select 4 aces as highlighted in Red in adjacent figure. Click “Add” to add them and then Click “Apply”

— 27 —


#

Description

Figure

Now we need to create Edge Group or Sub Meshes that we will create in the thickness o the Pressure Vessel and Nozzle. In the Create Group Window, Select the Second button to Add Edge. 39 Add all our edges that we had selected in previous chapter or the PV Shell and additional edges that are created due to partitioning o the PV in the middle o the Length.

40

Also Add our edges as shown in the adjacent figure which are on the Inside o Nozzle and on PV Shell, and give it a Name “PV_SubMsh”. “PV_SubMsh” should have 12 edges in it.

— 28 —


#

Description

41

Similarly we will create Edge group or “Noz_SubMsh” as shown in adjacent figure.

Figure

Tere will be 8 edges in “Noz_ SubMsh”

Tis concludes creating Geometry. 42 Save this file.

— 29 —


Step 4: Meshing using Notebook #

Description

Figure

We spend quiet a long time Modelling the Pressure vessel and Nozzle junction but it is well worth. 1

Due to the effort spent earlier, we will have to do less effort in Meshing the geometry. Select Mesh module in Salome-Meca.

Click on Mesh -> Create Mesh

2

Change the Name to “PV_ Mesh”. Click on the Button “Assign “Assign a set s et o hypotheses” and Select “3D: Automatic Hexahedralization Hexahedrali zation””

— 30 —


#

Description

Figure

Now in the next window it asks or Number o Segments or Global Mesh. We need to define Parameters or the Mesh Number o Segments in Notebook. 3

We will define: GlobalSeg with Value 15 PVSeg with Value 5 NozSeg with Value 5

4

In the window that pops up, change the Name to “Global Mesh Seg” and enter “GlobalSeg” as Number o Segments. Click “OK” Click “Apply and Close”

— 31 —


#

Description

Figure

Right Click “PV_Mesh” and Select “Create Sub-Mesh”. Change the Name to “PV_ Sub”, select “PV_SubMsh” or Geometry. 5 Select “Wire discretisation” or Algorithm. Click on the Gear button next to Hypothesis and Select “Nb. Segments”

6

In the window that pops up change the Name to “PV Tk Seg” and Number o Segments to “PVSeg” “PVSeg”.. Click “OK”

Back to window.

7

Create

sub-mesh

Click on the Gear button next to “Add. “Add. Hypothesis” and Select “Propagation o 1D Hyp. On opposite edges”. Tis will ensure that the sub mesh is propagated throughout the thickness. Click “Apply and Close”

— 32 —


#

Description

Figure

Do the same with “Noz_ SubMsh” and or the Number o Segments Seg ments use us e “NozSeg”. “NozSeg”. 8

Make sure that “Propagation o 1D Hyp. On opposite edges” has been selected. Click on “Apply and Close”

Right Click on “PV_Mesh” and Select “Compute”. As can be seen the total number o Edges, Faces and Volumes has been reduced. 9 Number o Volumes reduced rom 54000 to 15000. Tis will reduce the time taken t aken by Code_Aster to carry out FE Analysis.

— 33 —


#

Description

Figure

We need to create Mesh Groups rom Geometry Group. Right Click “PV_Mesh” and Select “Create Groups rom Geometry”. 10

Click on the Curved Arrow next to Geometry and Select “Press” rom Object Browser. Click “Apply” Do the same with “Dz0”, “LongPres”, “Norma” and “Force”

Tis concludes generation o Mesh. 11 Save this study.

Change Parameter in Notebook Now is the real test o Notebook. Once geometry and mesh is generated and the file has been saved, Click on File -> Notebook and change the parameters and see i the study updates. For example, change the value o PV_IR rom 1000 to 750 and Click “Update Study”. Salome will be perorming the steps that we carried out to generate geometry and mesh again and when done, it will present the final result. Our result is shown below.

— 34 —


John told Esha that using Notebook is very easy and updating geometry and mesh is done by just a click o a button, but as we noticed, Notebook is not powerul yet and complex ormulas cannot be entered. I you want to enter complex ormulas, you better edit the python file manually.

— 35 —


Summary John asked Esha to summarise what she learnt by doing this Parametric Modelling. Esha summarised it as below ▶

How to edit a Python file.

▶

How to enter Parameters in Python file.

▶

How to Use Parameters in Geometry and Mesh creation.

▶

How to use Notebook in Salome.

▶

How to add Parameters and its Value in the Notebook.

▶

What are the limitations o Notebook.

▶

How to update study by changing Parameters in the Notebook.

Endnotes 1

Parameters are called Variables

2

You can perorm arithmetic calculations in Variable Value field.

— 36 —

Adding Moments to a face in 3D model

Chapter 2 - Case 13 Adding Moments to a ace in 3D model John asked Esha about the next problem she wanted to solve. Esha was ready with her request and as soon as she heard John, she said that next she wanted to learn how to add Moment to a ace in 3D model. In previous chapters John has explained how to add orces on the Nozzle but in real lie, Piping engineers give her both Forces and moments on the nozzle ace which they have obtained rom their Pipe Stress analysis sofware. She knew how to add orces to the ace o a 3D model but now she wants to take it urther to add Moments.

— 37 —


Step 1: Description o the problem John thought or some time and then told Esha that by deault Code_Aster does not have any way in which Moments can be added to a ace as is evident rom U4.44.01. But there is a way to add that capability by enhancing the existing 3D model and entering Moment loads on the ace. o do this the mesh file has to be edited. A node has to be placed at a suitable location, connect this node to the ace on which we need to apply moment and then apply moment loads on the Node, which is allowed by Code_Aster. John said that we will use the same Pressure Vessel example we have used previously and enhance the mesh file.

Step 2: Input values or the FE analysis Dimensions o the Pressure Vessel are similar to the previous study. ID o Cylindrical shell o PV: 2000mm (2m) Tickness o Cylindrical shell o PV: 10mm (0.01m) Hal Length o Cylindrical shell o PV: 1500mm (1.5m) Dimensions o the Nozzle are ID o the Nozzle: 300mm (0.3m) Tickness o the Nozzle: 10mm (0.01m) Projection o Nozzle: 290mm (0.29m)

Step 3 and 4: Generating Geometry by Parametric Modelling and editing mesh John copied Python file “Case12.py” rom Case12 older, which is a parametric modelling and meshing file, and saved it as “Case13.py” in a separate older named Case13. Ten John double clicked the file to open it and made sure that the parameters defined in the python file are as per the geometry described in Step 2 above. Excerpt o “Case13.py” is shown below. #########################


#Pressure Vessel Outside Radius PV_OR = 1010 #Pressure Vessel Inside Radius PV_IR = 1000

— 38 —


#Pressure Vessel Height PV_Height = 1500 #Nozzle Outside Radius Nozz_OR = 160 #Nozzle Inside Radius Nozz_IR = 150 #Nozzle Protrusion Length Nozz_Protrusion = 290 #Height of Cylinder for Nozzle Construction Nozz_Len = PV_OR + Nozz_Protrusion #####################


#Number of Segments for Global Meshing GlobalSeg = 15 #Number of Segments for Pressure Vessel Shell Thickness Meshing PVSeg = 5 #Number of Segments for Nozzle Shell Thickness Meshing NozSeg = 5 ###################

#End of Parameters# ###################

— 39 —


#

Description

1

John started Salome-Meca, Clicked on File -> New and then File -> Load Script, he then went to the older where “Case13.py” was saved and then Opened it.

2

Once Salome-Meca generates the Geometry and Mesh you will be presented with the ollowing screen.

Figure

— 40 —


#

3

Description

Figure

Now we need to modiy this mesh, add a single node at the centre o the nozzle ace at the location shown in the ollowing figure with the red dot. Te red dot is in the same plane as that o the ace on which we applied Force.

4

Beore we go any urther we will save this file in Case13 older.

— 41 —


#

Description

Figure

Next we will create Groups in this mesh rom Geometry. Right Click PV_Mesh -> Create Group rom Geometry and then create ollowing groups. 5

Dz0 LongPres Norma Press Force Next we will create a New Node at the centre o the Nozzle. Click “PV_Mesh” in the Object Browser to select it. Click Modification -> Add -> Nodes In the window that opens, enter ollowing parameters

6

X: 1300 (Nozzle OR + Protrusion) Y: 0 Z: 750 ick “Add to group” and enter “ForceN” as Group Name 1. Tis will create a new group with only 1 node. Click “Apply and Close”

— 42 —


#

Description

Figure

Next we need to add this single node to the Face group “Force”, but a Face group cannot be added to a Node Group, so the Face group “Force” has to be converted to Node Group. Click Mesh -> Group o Underlying entities Use “ForceF” as the Result name2. 7

For Elements type select “Node” Click “Force” in the Object Browser under PV_Mesh -> Group o Faces and it will be added as shown in adjacent figure. Click “Apply and Close” Tis will convert the Face group “Force” to a Node group with all the nodes on that ace.

— 43 —


#

Description

Figure

Next we will make a Union o Node group “ForceF” and “ForceN”. Click Mesh -> Union Groups In the window that shows up enter “Solid” as Result name. 8

Click on “ForceN” and “ForceF” so that they will be added to the Arguments. Click “Apply and Close”. You should have three Node Groups in the mesh “PV_ Mesh” viz “ForceN”, “ForceF” and “Solid”.

We need to convert Linear mesh to Quadratic. 9

Right Click “PV” - > Convert to/rom quadratic In the window that opens just press “Apply and close”

Step 5, 6, 7, 8 and 9: Reusing .comm file rom Case9 and editing it John said that instead o creating the entire .comm file, we will re-use the .comm file rom Case9, modiy it and use it in this analysis. John said that there are differences between Code_Aster command file between version 10.x and 11.x but or most o the part, they are similar. Save “Case9.comm” to Folder Case13 and rename it as “Case13.comm” Entire Case13.comm is shown below. New commands added to “Case13.comm” are highlighted in RED colour. Tese commands are same between version 10.x and 11.x. Commands that are different between version 10.x and 11.x are highlighted in PURPLE colour. Comments are marked in GREEN colour.

— 44 —


#U4.11.01 DEBUT();

#U4.21.01 #### We need to dene mesh with the name “mesh1” mesh1=LIRE_MAILLAGE(FORMAT=’MED’,); #### We then create another mesh to accommodate the Point we created in Mesh Module mesh=CREA_MAILLAGE(MAILLAGE=mesh1, CREA_POI1=_F(NOM_GROUP_MA=’ForceN’, GROUP_NO=’ForceN’,),);

#U4.41.01 #### Here along with the 3D model which is associated to the whole Mesh, we associate ####

DIS_TR modelisation to the single Node.

DIS is short for Discrete,

####

T stands for Translation and R stands for Rotation which means that we can

####

associate Translation and most importantly Rotation to this model.

model=AFFE_MODELE(MAILLAGE=mesh, AFFE=(_F(TOUT=’OUI’, PHENOMENE=’MECANIQUE’, MODELISATION=’3D’,), _F(GROUP_MA=’ForceN’, PHENOMENE=’MECANIQUE’, MODELISATION=’DIS_TR’,),),);

#U4.43.01 SA285GrC=DEFI_MATERIAU(ELAS=_F(E=2.1e5, NU=0.3, RHO=7.8e-9,),); material=AFFE_MATERIAU(MAILLAGE=mesh, AFFE=(_F(TOUT=’OUI’, MATER=SA285GrC,),),);

#U4.44.01 Dz0=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Dz0’,DZ=0,),); Norma=AFFE_CHAR_MECA(MODELE=model, FACE_IMPO=_F(GROUP_MA=’Norma’,DNOR=0,),); Norma1=AFFE_CHAR_MECA(MODELE=model, LIAISON_UNIF=_F(GROUP_MA=’Norma’,DDL=(‘DX’,),),); #### We specify that the node group formed from the UNION of face and single node behave

— 45 —


####

as a solid which means that any force / moment applied to the single node will

####

be applied to the whole face.

Solid=AFFE_CHAR_MECA(MODELE=model, LIAISON_SOLIDE=_F(GROUP_NO=’Solid’,),);

#U4.44.01 Press=AFFE_CHAR_MECA(MODELE=model, PRES_REP=(_F(GROUP_MA=’Press’, PRES=1,),),); LongPres=AFFE_CHAR_MECA(MODELE=model, PRES_REP=(_F(GROUP_MA=’LongPres’, PRES=-49.7512,),),); ForcBal=AFFE_CHAR_MECA(MODELE=model, PRES_REP=(_F(GROUP_MA=’Force’, PRES=-7.2581,),),); Force=AFFE_CHAR_MECA(MODELE=model, FORCE_FACE=(_F(GROUP_MA=’Force’, FY = 1.0268,),),); #### We dene moment in X direction with the value of 10,000 N.mm which will behave as ####

torque on the nozzle

Moment=AFFE_CHAR_MECA(MODELE=model, FORCE_NODALE=_F(GROUP_NO=’ForceN’, MX=10000.0,),);

#U4.31.02 #### Here Moment is given a stepping function. ####

are from Case 9 and carried forward.

Moment is Zero for rst four steps (which In step 5 and 6, we apply moment

Moment1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(2,0,3,0,4,0,5,1,6,1,), PROL_GAUCHE=’CONSTANT’, PROL_DROITE=’CONSTANT’,); #### We have to change all stepping functions and add steps 5 and 6. ####

Step 5 will be zero

for all loads except Moment and in step 6, all loads will be applied simultaneously.

Force1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(2,1,3,0,4,1,5,0,6,1,), PROL_GAUCHE=’CONSTANT’, PROL_DROITE=’CONSTANT’,); Press1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(2,0,3,1,4,1,5,0,6,1,), PROL_GAUCHE=’CONSTANT’, PROL_DROITE=’CONSTANT’,); LPres1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(2,0,3,1,4,1,5,0,6,1,), PROL_GAUCHE=’CONSTANT’, PROL_DROITE=’CONSTANT’,); ForcBal1=DEFI_FONCTION(NOM_PARA=’INST’,

— 46 —


VALE=(2,0,3,1,4,1,5,0,6,1,), PROL_GAUCHE=’CONSTANT’, PROL_DROITE=’CONSTANT’,); list=DEFI_LIST_REEL(DEBUT=2, INTERVALLE=_F(JUSQU_A=6, PAS=1,),);

#### Here we give element parameters to the single Node.

It is given a CARA of K_TR_D_N,

####

where K stands for Stiffness matrix

####

TR stands for Translation and Rotation

####

D stands for Only diagonal matrix

####

N stands for Node.

####

This is associated with Mesh Group ForceN dened in Salome

####

and has a stiffness of 0.1 for all 6 parameters which means, it is very soft and

####

it will not resist any loads but will only be used to transfer the full load and

####

NOT change the load due to its stiffness

element=AFFE_CARA_ELEM(MODELE=model,

DISCRET=_F(CARA=’K_TR_D_N’,

GROUP_MA=’ForceN’,

VALE=(0.1,0.1,0.1,0.1,0.1,0.1,),),);

result=MECA_STATIQUE(MODELE=model, CHAM_MATER=material, CARA_ELEM=element,

EXCIT=(_F(CHARGE=Dz0,),

_F(CHARGE=Norma,),

_F(CHARGE=Norma1,), _F(CHARGE=Solid,), _F(CHARGE=Press, FONC_MULT=Press1,), _F(CHARGE=LongPres, FONC_MULT=LPres1,), _F(CHARGE=ForcBal, FONC_MULT=ForcBal1,), _F(CHARGE=Force, FONC_MULT=Force1,), _F(CHARGE=Moment, FONC_MULT=Moment1,), ),

— 47 —


LIST_INST=list,);

#These items are manually added which are different between version 10.x and 11.x result=CALC_CHAMP(reuse=result,

RESULTAT=result,

CONTRAINTE=(‘SIGM_ELNO’,’SIGM_NOEU’),

CRITERES=(‘SIEQ_ELNO’,’SIEQ_NOEU’,),);

#U4.91.01 IMPR_RESU(FORMAT=’MED’, UNITE=80, RESU=_F(MAILLAGE=mesh, RESULTAT=result, TOUT_CHAM=’OUI’, TOUT_CMP=’OUI’,),);

#U4.11.02 FIN();

With this inormation in the .comm file we start the analysis.

— 48 —


Step 10: Run the analysis Now we just need to add an Aster case in Salome-Meca and run the Analysis. Enable Aster Module in SalomeMeca. #

Description

Figure

Click Aster -> Add Study case. Give it a Name “P1F10M10”.

1

For the Command file select “rom disk” and then click on the Page Icon next to drop down and select “Case13. comm” that we created in last step. For the Mesh, click on the Curved arrow and Select “PV”. Change otal memory to “1024” and ime(s) to “1200”. Click “OK” A new branch will be created called “Aster” in Object Browser.

2

Right Click “P1F10M10” and Select “Run” I everything goes well, you will see “Post-Pro” module added to the Object Browser.

— 49 —


Step 11: Post Processing o the Results Enable Post-Pro Module in Salome-Meca and let’s compare the results we obtained rom this analysis with those that we obtained rom Chapter 9. #

Description

Figure

Open P1F10M10.rmed branch till you see “result___DEPL.” You will be able to see five branches 2, 3, 4, 5 and 6. Tese are the load cases that we had defined in our Analysis. 1

All results will have these five load cases. First Tree load cases should match those o Chapter 9 o the previous book. Result 5 and 6 are the ones that we are interested in.

— 50 —


#

Description

Figure

Right Click “2. _” in result___ DEPL and check that the Deormed Shape with Scale Factor o “50” and Scalar Mode o “” is equal to 1.39966 (result rom Chapter 9). 2

Change the Representation to “Surace” and enable op View As can be seen in the adjacent figure, the deormation o the nozzle in +Y direction is 1.39405 which closely match that o Chapter 9.

Right Click “3. _” in result___ DEPL to check the deormed shape due to Internal Pressure only. 3

4

As can be seen in the adjacent figure, the deormation along the radial direction o Pressure Vessel is 0.813529 which again closely matches with Chapter 9 o 0.877668.

By checking deflections o Step 2 and 3 it is evident that the results matches that o Chapter 9. Now let’s check the result or Moment.

— 51 —


#

Description

Figure

Right Click “5. _” in result___ DEPL and see Deormed Shape with Deault Scale Factor and Scalar Mode o “”.

5

As can be seen in the adjacent figure, the deormation is very small which is obvious as the moment applied is too small. On urther checking and rotating the model it can be seen that the deormation is similar to the one that can be obtained by twisting the nozzle. Next we will check the Stresses in the model or step 5 and 6 only.

6

Right Click “5. __” in result___ SIEQ_NOEU and Select Scalar Map. Keep everything deault in the window that pops up except or Scalar Mode select “[1.] VMIS, -”. As can be seen in the figure below, when only Moment o 10,000Nmm is applied, the stresses in the entire geometry is less than 0.02MPa which is very small compared to other stresses due to only pressure and only orce.

— 52 —


#

Description

Figure

7

Right Click “6. __” in result___ SIEQ_NOEU and Select Scalar Map. Keep everything deault in the window that pops up except or Scalar Mode select “[1.] VMIS, -”. 8

As can be seen in the figure below, when all three loads Pressure o 1MPa, Force o 10,000N and Moment o 10,000Nmm is applied, the maximum stress generated in the model is around 319.15MPa. Te stress in the PV shell remote to the Nozzle is around 87MPa which is in line with the Pressure Only load case and the FE analysis we carried out previously o the PV shell.

— 53 —


#

Description

Figure

9

10

John saved the file and closed Salome-Meca.

— 54 —


Summary John asked Esha to summarise what she learnt by doing this Finite Element Analysis. Esha summarised it as below ▶

How to add a Node to an existing mesh.

▶

How to create a Node group rom Face group in a mesh.

▶

How to make a Union o two Node Groups.

▶

How to add a Node to a .comm file

▶

What to enter or the stiffness o a Node used or applying loads only

▶

How to add Moments to a 3D geometry

▶

How to validate your current analysis with previous analysis or hand calculation

Endnotes 1

ForceN signifies that it is a single Node on which orce has to be applied. Tis convention is or the ease o understanding or the user. Make sure that the length o name is less than 8 characters.

2

ForceF signifies that it is a group created rom Face

— 55 —


Notes:

— 56 —

Combining Element types in a single FE Analysis

Chapter 3 - Case 14 Combining Element types in a single FE Analysis Esha was happy to become a student again and wanted to learn more rom John. She asked John that in one o her calculations, the 3D model was very huge with large number o nodes. Some o the parts o this model were remote and o no interest to the study but as she didn’t know any other way she had to model the entire geometry. Tis study took very long to complete and i she had incorrectly used input values, she had to repeat everything again. She asked John i there was a way to combine elements in a single model. May be combine plates or shells with 3D model or combine beams with shells or beams with 3D models. John smiled at her and said that he had a perect solution or her.

— 57 —


Step 1: Purpose o the FE Analysis / Description o the problem Te geometry and loading or this study remains the same as that o a Pipe Guide 3D analysis that was carried out in chapter 7 o previous book. But or this study we will combine 3 Dimensional model with Plates and Beams and perorm a Linear Static FE analysis. John urther added that the length o Guide (150mm) will be divided into 3 parts. First 50mm near the fixed support will be modelled as 3D, next 50mm as plate and the last 50mm as beam.

Step 2: Input values or the FE analysis Input values or the Analysis remains same as previously carried out in chapters 3, 6 and 7. Tey are shown here or reerence. Dimensions o the Pipe Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 150mm Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Force applied to this plate: 2000N (2kN)

Step 3: Model Geometry John started Salome-Meca and created a new study. He started Geometry Module and began creating model o Pipe guide.

— 58 —


#

Description

Figure

For generating Pipe Guide model with all three types o elements, John started with the use o Primitive shape. 1

Click New Entity -> Primitives -> Box and enter the values as shown in the figure and leave its Name as Box_1. Click on “Apply and Close”.

Next we need to create plate element or the second part o the model. Click New Entiry -> Basic -> 3D Sketch. In the window that pops up enter X: 50, Y: 0, Z: 5, Click “Apply” 2

Ten enter X: 100, Y: 0, Z: 5, Click “Apply” X: 100, Y: 100, Z: 5, Click “Apply” X: 50, Y: 100, Z: 5, Click “Apply” Click “Sketch Closure”

— 59 —


#

Description

Figure

Now we will make a ace out o this 3D sketch. Click New Entity -> Build -> Face 3

In the window that pops up keep the deault Name “Face_1” Make sure that “3D Sketcher_1” is selected as Objects and ensure that “ry to create a planar ace” is Checked. Click “Apply and Close”

Next to make a beam we need a straight line and or that we need two points. Click New Entity -> Basic -> Point

4

Change Name to “P1” and enter X: 100, Y: 50, Z: 5 Click “Apply” Name “P2” X: 150, Y: 50, Z: 5 Click “Apply and Close”

5

With the deault settings, visualising points is very hard so change the Parameters such that the points can be seen big. Click File -> Preerences and make sure you have ollowing parameters or “Marker o Point”.

— 60 —


#

Description

Figure

6

Now let’s create a line between Points P1 and P2. Click New Entity -> Basic -> Line 7

In the window that pops up keep deault name “Line_1” and select “P1” as Point 1 and “P2” as Point 2. Click “Apply and Close”

— 61 —


#

Description

8

Te final model with only “Box_1”, “Face_1” and “Line_1” visible should look like adjacent figure.

Figure

Next we need to make a compound out o all three so that it can be meshed properly. Click New Entity -> Build -> Compound. 9 In the window that pops up change the Name to “Guide” and select “Box_1”, “Face_1” and “Line_1” as Objects. Click “Apply and Close”

— 62 —


#

Description

Figure

Now we will create group o Plate and Beam rom the Compound Guide so that we can give dimensions to these elements in command file.

10

While “Guide” is selected in Object Browser Click New Entity -> Group -> Create In the window that pops up Enter Name “Plate” and select the only surace in the model. Click “Add” and then “Apply”

— 63 —


#

11

Description

Figure

In the Create Group window, Change the Shape ype to “Edge” (Second Option), Enter Name “Beam” and select the only edge in the Model. Click “Add” and then “Apply”

Create a Face group Named “Fix” similar to Chapter 7 in previous Book (Face on YZ plane). 12

For the group Named “Load” change the Shape ype to “Point” (First Option) and select the Point as shown in the adjacent figure. Click “Add” and “Apply”

— 64 —


#

Description

Figure

13

Now comes the important part in which we will describe the groups which will connect with each other and orm a solid entity whereby the displacements, orces and moments can be transerred between different element types. We will have to define two linkages, first between Volume and Plate and second between the Plate and Beam In the Create Group window, Change the Shape ype to “Face” (Tird Option), give it a Name “Solid1_1” and select the ace highlighted with Pink colour in the adjacent figure. Click “Add” and then “Apply”

14 Change the Shape ype to “Edge” (Second Option), give it a Name “Solid1_2” and select the edge highlighted with Yellow colour in the adjacent figure. Click “Add” and then “Apply”

In the Create Group window, keep the Shape ype as “Edge” (Second Option), give it a Name “Solid2_1” and select the edge highlighted with Yellow colour in the adjacent figure. Click “Add” and then “Apply” 15 Change the Shape ype to “Point” (First Option), give it a Name “Solid2_2” and select the point highlighted with Blue colour in the adjacent figure. Click “Add” and then “Apply and Close”

— 65 —


#

Description

16

Your Object Browser should look like adjacent figure.

Figure

Tis concludes Geometric modelling or this Analysis 17 John saved this file as “Case14.hd ” at a convenient location

— 66 —


Step 4: Meshing Geometry John changed Geometry Module to Mesh Module and began creating mesh o Pipe guide. #

Description

Figure

Make sure that “Guide” is selected in Object Browser. Click Mesh -> Create Mesh.

1

In the dialogue box that pops up, Click “Assign a set o hypotheses” and Select “3D: Automatic Hexahedralization”. In the window or Hypotheses Construction enter “10” or Number o Segments and Click “OK”. Click “Apply and Close” in Create Mesh window.

Right Click “Mesh_1” and Select “Compute” 2 Final mesh looks like adjacent figure.

— 67 —


#

Description

3

Right Click “Mesh_1” and select “Create Groups rom Geometry” and or each Group Name in geometry, viz. Plate, Beam, Fix, Load, Solid1_1, Solid1_2, Solid2_1 and Solid2_2, create Mesh Groups.

4

Afer this exercise your Object Browser should look like adjacent figure.

Figure

— 68 —


#

Description

Figure

Next, we need to create two Group o Nodes “Solid1” and “Solid2”. For this we need to convert Group o Edges “Solid1_2” and “Solid2_1” and Group o Faces “Solid1_1” to Group o Nodes.

5

Click Mesh -> Group o underlying entities and in the window that pops up give “Solid1_2” as Result name and make sure that Elements type is selected as Node and “Solid1_2” is selected in Arguments. Click “Apply” Similarly do the same exercise or “Solid2_1” and “Solid1_1”.

— 69 —


#

Description

Figure

Now we will make a union o “Solid1_1” and “Solid1_2” to orm “Solid1”.1

6

Click Mesh -> Union Groups and Enter “Solid1” as Result name. For Arguments Select “Solid1_1” and “Solid1_2” rom Object Browser. Click “Apply” Similarly create Group “Solid2” with Arguments “Solid2_1” and “Solid2_2”.

7

Tis concludes creating Mesh. Save the file.

Step 5, 6, 7, 8 and 9: Generating command file by hand John said that here we will copy the command file o Case7 and re-use it by making necessary changes to it. Te entire command file is shown below. Important changes are highlighted in RED colour. Comments are marked in GREEN colour or easy reerence.

#U4.11.01 DEBUT();

#U4.21.01 mesh=LIRE_MAILLAGE(FORMAT=’MED’,);

#U4.22.01

— 70 —


mesh=DEFI_GROUP(reuse=mesh, MAILLAGE=mesh, CREA_GROUP_MA=_F(NOM=’TOUT’, TOUT=’OUI’,), CREA_GROUP_NO=_F(TOUT_GROUP_MA=’OUI’,),);

#In dening model we need to specify that there are #DKT (Plate) and POU_D_T (Beam) elements as well. #U4.41.01 model=AFFE_MODELE(MAILLAGE=mesh, AFFE=(_F(TOUT=’OUI’, PHENOMENE=’MECANIQUE’, MODELISATION=’3D’,), _F(GROUP_MA=’Plate’, PHENOMENE=’MECANIQUE’, MODELISATION=’DKT’,), _F(GROUP_MA=’Beam’, PHENOMENE=’MECANIQUE’, MODELISATION=’POU_D_T’,),),);

#Next we will dene the geometry of the plate and beam. #U4.42.01 element=AFFE_CARA_ELEM(MODELE=model, POUTRE=_F(GROUP_MA=’Beam’, SECTION=’RECTANGLE’, CARA=(‘HY’, ‘HZ’,), VALE=(100, 10,),),

COQUE=_F(GROUP_MA=’Plate’, EPAIS=10,),);

#U4.43.01 CS=DEFI_MATERIAU(ELAS=_F(E=2.1e5, NU=0.3, RHO=7.8e-9,),);

#U4.43.03 material=AFFE_MATERIAU(MAILLAGE=mesh, AFFE=(_F(TOUT=’OUI’, MATER=CS,),),);

#U4.44.01

— 71 —


Fixed=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix’, DX=0, DY=0, DZ=0,),);

#U4.44.01 ForceZ=AFFE_CHAR_MECA(MODELE=model, FORCE_NODALE=(_F(GROUP_NO=’Load’, FZ = 2000,),),); #To make connection between Volume and Face LIAISON_SOLID is used #This enables forces, moments and displacements to be projected considering the connection #as a solid entity. Solid1=AFFE_CHAR_MECA(MODELE=model, LIAISON_SOLIDE=_F(GROUP_NO=’Solid1’,),);

#To make connection between Face and Edge again LIAISON_SOLID is used Solid2=AFFE_CHAR_MECA(MODELE=model, LIAISON_SOLIDE=_F(GROUP_NO=’Solid2’,),);

result=MECA_STATIQUE(MODELE=model, CHAM_MATER=material, CARA_ELEM = element, EXCIT=(_F(CHARGE=Fixed,),

_F(CHARGE=ForceZ,), _F(CHARGE=Solid1,),

_F(CHARGE=Solid2,),),);

#U4.81.04 result=CALC_CHAMP(reuse=result, RESULTAT=result,

— 72 —


CONTRAINTE=(‘SIEF_ELNO’, ‘SIPO_ELNO’, ‘EFGE_NOEU’, ‘SIPO_NOEU’, ‘SIEF_ELGA’,’SIGM_ELNO’, ‘SIGM_NOEU’,), CRITERES=(‘SIEQ_ELNO’,’SIEQ_NOEU’,), FORCE=(‘REAC_NODA’,),);

#U4.91.01 IMPR_RESU(FORMAT=’MED’, UNITE=80, RESU=_F(MAILLAGE=mesh, RESULTAT=result, TOUT_CHAM=’OUI’, TOUT_CMP=’OUI’,),);

#U4.11.02 FIN();

Tis completes the steps to generate a command file, now we want to generate Aster study case.

— 73 —


Step 10: Run the analysis #

Description

Figure

Click Aster -> Add study case. A new window will pop up. Give a Name “Guide2K”

1

For Command File, Select “rom disk” rom the drop down menu and then select the “Case14.comm” file we created earlier. For Mesh File, Select “rom object browser” and then select the “Mesh_1” rom Object Browser. Keep ASK services as deault. Change otal memory to 1024MB and ime to 1200s.

2

Right Click “Guide2K” and Select “Run”

— 74 —


#

Description

3

I you have done everything correctly, Analysis should complete and you should be able to see “Post-Pro” branch added to the Object Browser

Figure

— 75 —


Step 11: Post Processing o the Results John enabled “Post-Pro” module and opened Post-Pro branch. John wanted to demonstrate that the deflection in this analysis is comparable to the previous studies o 1D and shell Analysis which should be around 1.29mm. #

Description

Figure

1

John opened result_DEPL branch, opened “0”, Right Click it and Selected “Deflected Shape”. Te maximum deflection that Salome-Meca was showing her was 1.11675mm which is close to 1.29mm.

— 76 —


#

Description

Figure

John told Esha that as there are different elements, not all results are ound in one place, so we will have to mix and match the results.

2

John opened result_SIEQ_ NOEU branch, opened “0”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “VMIS” in “Scalar Mode” and change the range to “Use imposed range” rom 0 to 200. Set Orientation to Vertical Click “OK”

— 77 —


#

3

Description

Figure

Next John opened result_ SIEF_ELGA branch, opened “0”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “SIXX” in “Scalar Mode”, “Minimum” or “Gauss Matric”, Use imposed range rom -200 to 0. Set Orientation to “Vertical” Set Origin X value to 0.11

— 78 —


#

Description

Figure

Next Click Input ab.

4

ick “Use Only Groups” and add “Plate” to the right hand side as shown in adjacent figure. Click “OK”

— 79 —


#

Description

5

Ten John opened result_ SIPO_NOEU branch, opened “0”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “SMFY” in “Scalar Mode”, Use imposed range rom -200 to 0.

Figure

Set Orientation to “Vertical” Set Origin X value to 0.21 Click “OK”.

Afer all modification have been made the final result looks like figure shown below. Here when we check the values o Beam, they are rom 0 to -60 MPa which makes sense as Beam is o 1/3 length o the total Guide. 6

When we check the value o Plate, they are rom -67 to -115 MPa at the centre o the element at Gauss Point, which again makes sense as this Plate is o 1/3 length o the total Guide and is in between Volume and Beam. When we check the value o Volume, VMIS stresses are rom 0 to 197 MPa which is similar to the results we obtained in 3D analysis.

— 80 —


#

Description

Figure

John said that by using mixed elements, the results are not affected and the computing power required reduces.

Summary John asked Esha to summarise her findings and what she had learned. ▶

How to model multiple elements in a single geometry

▶

How to mesh multiple elements in a single mesh file

▶

How to define Mesh connections or interconnection between volume, plate and beam

▶

How to generate command file taking into consideration multiple elements

▶

How to Post-Process final result considering multiple elements.

Endnotes 1

Tis can be done in command file as well but it is better to do as much as possible in Salome.

— 81 —


Notes:

— 82 —

Non-Linear Material FE Analysis

Chapter 4 - Case 15 Non-Linear Material FE Analysis At this point in time, Esha was smiling and was happy to have learnt urther. John asked Esha i there was anything else that she wanted to learn and Esha jumped up and said Non-Linear analysis please. John started smiling at the enthusiasm o Esha and continued. John asked Esha i she knew what types o Non-Linear FE analysis are there. Esha said that there are three main types o Non-Linear FE analysis, one is where the material properties are non-linear, second is when the geometry is nonlinear and third is when there is contact/riction which creates a non-linear FE analysis. Esha said that she wanted to learn NonLinear Material and Contact FE Analysis next. Excellent, said John and continued that, in this analysis we will look at Non-Linear material FE analysis.

— 83 —


Step 1: Purpose o the FE Analysis / Description o the problem Te geometry that will be analysed is that o an elongated Pipe Guide which had to be designed due to constraints in space around the piping. Te geometry, material properties and loading or this study are noted below. For this study we will use 3 Dimensional model with Non-Linear Material and perorm a Non-Linear Static FE analysis. Yield strength o Carbon Steel used in this study is 300MPa.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Pipe Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 500mm Material Properties o the Pipe Guide are as ollows Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Yield strength: 300 MPa Force applied to this plate: 2000N (2kN)

— 84 —


Step 3: Model Geometry John asked Esha to generate the Geometry and Mesh it with hexahedral mesh. Esha started Salome-Meca and created a new study. She started Geometry Module and began creating model o Pipe guide. #

Description

Figure

For generating Pipe Guide model, Esha started with the use o Primitive shape. 1

2

Click New Entity -> Primitives -> Box and enter the values as shown in the figure and change its Name to “Guide”. Click on “Apply and Close”.

Create Face groups or “Fix” boundary condition and “Load” boundary condition as carried out in Chapter 7 o previous Book.

— 85 —


#

Description

3

Tinking orward Esha decided that she will need a Sub Mesh or the thickness with density o 5 and so she made an Edge group “Sub_5” as shown in adjacent figure.

Figure

Tis concludes Geometric modelling or this Analysis 4 Esha saved this file as “Case15.hd” to a convenient location

— 86 —


Step 4: Meshing Geometry Esha changed Geometry Module to Mesh Module and began creating mesh o Pipe guide. #

Description

Figure

Click Mesh -> Create Mesh. In the dialogue box that pops up, Click “Assign a set o hypotheses” and Select “3D: Automatic Hexahedralization”. 1

In the window or Hypotheses Construction enter “50” or Number o Segments and Click “OK”. Click “Apply and Close” in Create Mesh window. Mesh density o 50 or the thickness is an overkill. As per pre-planning Esha specified a Sub-Mesh with number o segments “5”.

2

Right-Click “Mesh_1” -> Sub Mesh. In the Sub Mesh window select “Sub_5” or Geometry. Select “Wire discretisation” or Algorithm and “Nb. Segments” or Hypothesis. Enter “5” or Number o Segments Click “OK”

— 87 —


#

Description

Figure

Select “Propagation o 1D Hyp. On Opposite Edges” or Add. Hypothesis. 3

Sub Mesh window looks like adjacent figure. Click “Apply and Close”

Right Click Compute.

Mesh_1

->

4 Final Mesh should look like adjacent figure.

— 88 —


#

5

Description

Figure

Right Click Mesh -> Create Group rom Geometry and in the window that pops up Select “Fix” and “Load” rom Geometry. Click “Apply and Close”

Right Click “Mesh_1” Export -> MED.

6

->

In the window that opens enter “Guide_nl” or the File name and Click “Save” By deault this file will be saved in the same location as the HDF file.

7

Tis concludes creating Mesh. Save the HDF file.

— 89 —


Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Esha handed the reins o the analysis to John or Non-Linear FE analysis. John said that here we will make the comm file by using Efficient and then modiy it by making necessary changes or running Non-Linear analysis. #

Description

1

In Mesh ab, keep everything deault

Figure

— 90 —


#

Description

2

In Analysis ab, everything deault.

Figure

keep

3

In Material ab, Enter the inormation as shown in the adjacent figure

4

We don’t need to enter anything or Element ab

— 91 —


#

5

Description

Figure

In Boundary Condition(s) ab, Enter the inormation or restricting ace “Fix” in All three directions as shown in the figure. Click on “Add”

Now we need to enter a Load o “2000N” in Z direction on Face “Load”.

6

Enter “Load” or Load Name, Select “Force on Face” or Load ype, Enter “Load” or Is Assigned to. Finally Enter “-2” or FZ. 1 Click “Add”. For this study we do not need to enter Stepping unction or Loads.

— 92 —


#

7

Description

Figure

For the Output type, Select “SIEQ_NOEU” as we want to get VonMises stresses on Nodes in MED file. Click “Add”

Click “Save .comm file”. 8

Save it in the location where you saved the study.

Te entire command file generated by Efficient is shown below. Comments related to Efficient sofware has been removed rom the command file or easy reading. Important changes or making this command file suitable or Non-Linear analysis are highlighted in RED colour. Comments are marked in GREEN colour or easy reerence. Following is the list o changes that will be perormed on the command file: 1. Change linear material to non-linear material 2. Add Stepping unction or Load

— 93 —


3. Add Stepping unction or Non-Linear Analysis 4. Perorm analysis or Non-Linear setup 5. Save MED file with Non-Linear analysis results

#U4.11.01 DEBUT();


#U4.41.01 model=AFFE_MODELE(MAILLAGE=mesh, AFFE=_F(TOUT=’OUI’, PHENOMENE=’MECANIQUE’, MODELISATION=’3D’,),);

#U4.43.01 ####SY=300.0 species the Yield Strength of the Material ####D_SIGM_EPSI=0 suggest that after Yield Strength is reached ####

the slope of Stress Strain line is 0

CS=DEFI_MATERIAU(ELAS=_F(E=2.1e5, NU=0.3, RHO=7.8e-9,), ECRO_LINE=_F(D_SIGM_EPSI=0, SY=300.0,),);


#U4.44.01 Fix=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix’,DX=0,DY=0,DZ=0,),);

#U4.44.01 ####Force on Face will be increased from 0 to Full Load in time 0 to 1 #### Force on Face will be kept constant at Full Load from time 1 to 1.1 #### Force on Face will be reduced from Full Load to 0 in time 1.1 to 2.1

— 94 —


####

Load1 is the ramp function for Force on Face “Load”

Load=AFFE_CHAR_MECA(MODELE=model, FORCE_FACE=(_F(GROUP_MA=’Load’, FZ = -2,),),); Load1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(0.0,0.0,1.0,1.0,1.1,1.0,2.1,0.0),);

####The load increment is done in steps of 0.1 (PAS=0.1) ####The load will be increased manually (METHODE=’MANUEL’) ####

step1 is the list of steps (with maximum step of 2.1 and increment of 0.1)

####

maximum step1 of 2.1 corresponds to the Load1 maximum time of 2.1

####

in which step1 will be incremented (Manually)

step1=DEFI_LIST_REEL(DEBUT=0.0, INTERVALLE=_F(JUSQU_A=2.1, PAS=0.1,),); step=DEFI_LIST_INST(DEFI_LIST=_F(METHODE=’MANUEL’, LIST_INST=step1,),);

####Linear Calculations are carried out and stored as result for comparison purpose result=MECA_STATIQUE(MODELE=model, CHAM_MATER=material,

EXCIT=(_F(CHARGE=Fix,),

_F(CHARGE=Load,),

),);

#U4.81.04 result=CALC_CHAMP(reuse=result, RESULTAT=result, CONTRAINTE=(‘SIGM_ELNO’,’SIGM_NOEU’,), CRITERES=(‘SIEQ_ELNO’,’SIEQ_NOEU’,), FORCE=(‘REAC_NODA’,),);

####Non-Linear Calculations are carried out and stored as res_nl ####STAT_NON_LINE calculates Non Linear calculation ####We are using the same MODELE, material and Fix boundary condition ####We have added a stepping function “Load1” to Force on Face “Load” ####Refer to U4.51.11 for COMP_INCR

— 95 —


####RELATION=’VMIS_ISOT_LINE’ is used when Elastic-Plastic material is dened with ECRO_LINE ####

Refer to U4.51.11 Section 3.1.3 for DEFORMATION

####INCREMENT is the stepping function that the analysis will use ####NEWTON species the characteristics of Newton-Raphson ####

method of resolution of non-linear problems

####CONVERGENCE species the convergence criteria. ####

Here it is specied that

maximum of 10 iterations to be carried out for each step.

res_nl=STAT_NON_LINE(MODELE=model, CHAM_MATER=material, EXCIT=(_F(CHARGE=Fix,), _F(CHARGE=Load, FONC_MULT=Load1,),),

COMP_INCR=_F(RELATION=’VMIS_ISOT_LINE’, DEFORMATION=’SIMO_MIEHE’, TOUT=’OUI’,),

INCREMENT=_F(LIST_INST=step,), NEWTON=_F(REAC_INCR=1, MATRICE=’TANGENTE’, REAC_ITER=1,),

CONVERGENCE=_F(ITER_GLOB_MAXI=10,), );

res_nl=CALC_CHAMP(reuse=res_nl, RESULTAT=res_nl, CONTRAINTE=(‘SIGM_ELNO’,’SIGM_NOEU’,), CRITERES=(‘SIEQ_ELNO’,’SIEQ_NOEU’,), FORCE=(‘REAC_NODA’,),);

#U4.91.01 IMPR_RESU(FORMAT=’MED’, UNITE=80, RESU=_F(MAILLAGE=mesh, RESULTAT=result, NOM_CHAM=(‘DEPL’, ‘SIEQ_NOEU’,),),);

— 96 —


####We will store the results for Non-Linear calculation in a MED le as well ####Logical Unite for this MED le is “81” which will be used in Aster IMPR_RESU(FORMAT=’MED’, UNITE=81, RESU=_F(MAILLAGE=mesh, RESULTAT=res_nl, NOM_CHAM=(‘DEPL’, ‘SIEQ_NOEU’,),),);

#U4.11.02 FIN();

Tis completes the steps to generate command file, now we want to generate Aster study case using ASK.

— 97 —


Step 10: Run the analysis John activated Aster Module in Salome-Meca and then instead o a simple Aster study case he started ASK. In Salome-Meca, start Aster Module and then click Aster -> ools -> Run ASK #

Description

1

When ASK opens, it should look similar to the adjacent figure.

2

Figure

Click File -> Save, ASK will ask i you would like to Save the current environment. Click “YES”

Ten it will show you a dialogue box o where do you want to save the file. 3

Navigate to the location where you want to save the file and give it a meaningul name. Here we have used “Guide_nl”. Click “Ok”.2

— 98 —


#

Description

Figure

Afer that you need to give ASK a Base path rom where it will be able to get MED files and where it should save the results. 3 4

Click on the Folder Icon adjacent to the ext Box adjacent to “Base Folder” and navigate to the place where we saved the .astk file. Click “Ok”.

5

Click on the New File Icon in ASK main window as highlighted in the adjacent figure and a new line will be added to ASK.

In the new line that is created we need to speciy which file we want to add to this study. You can select what type o file you want to add to the study by clicking on the selection box under “ype” You don’t need to change the Server name as most o the analysis will be run on your Local computer. 6

In the name field you write the names o the files. For example the ype o file is “comm” so we write the name o the file “Assembly.comm” in the Name field. “LU” is the unit o file (Remember UNIE=80) “D” i ticked itmeans that the file is an Input file (.comm and MED files) “R” i ticked means that the file is an Output file (Message, Error, MED files) “C” i ticked means that the file will be Compressed (to save space)

— 99 —


#

Description

7

For our study, we will write the name “Case15.comm” file as shown in adjacent figure.4

8

Click on the new File icon. Change the ype to “mail” and enter the Name “Guide_ nl.med” with a LU o “20”.

9

Click on the new File icon. Change the ype to “mess” (Message file) and enter the Name “Guide_nl.mess”.

Figure

— 100 —


#

Description

10

Click on the new File icon. Change the ype to “resu” (Result file – ext file) and enter the Name “Guide_nl.resu”.

11

Click on the new File icon. Change the ype to “erre” (Error file) and enter the Name “Guide_nl.erre”.

12

Figure

Click on the new File icon. Change the ype to “rmed” (Result MED file) and enter the Name “Res_li.med” with a LU o “80”. (Tis is the result o Linear Analysis) Click on the new File icon. Change the ype to “rmed” and enter the Name “Res_nl.med” with a LU o “81”. (Tis is the result o Non-Linear Analysis)

— 101 —


#

Description

Figure

13

As we are used to increasing the Memory and time in Aster in Salome-Meca Wizard, let’s do it here as well. 14

Increase the memory to “1024 and time to “15:15:00”. Click on interactive ollow-up i you would like to see what is happening behind the scenes and at what step Code_Aster is.

— 102 —


#

Description

Figure

15

Finally Click File -> Save to save the ASK file and then Click on “Run” (not “run” as that is or selecting whether you want to Run the analysis or Debug it.

16

I everything goes well, you will be able to see all the result files that we had asked Code_Aster to generate viz. Message file, Result file etc. along with “Res_ li.med” and “Res_nl.med” files in the older.

John urther added that or a Non-Linear calculation, i or some reason the analysis cannot be computed (excessive stress beyond yield or the entire cross section o the geometry), Code-Aster will sub-divide the time rame and try to perorm the calculation. Tis can also happen i there are some errors in the calculation. Read the .mess file careully to find out the reason or error. I the reason or error is that the geometry has yielded, reduce the load and perorm the analysis again.

— 103 —


Step 11: Post Processing o the Results John enabled “Post-Pro” module. #

Description

Figure

Click File -> Import -> MED file. A new window opens. John selected “Res_li.med” file. Click File -> Import -> MED file. A new window opens. John selected “Res_nl.med” file. 1

Both o these files should be loaded in Salome-Meca. John opened result_DEPL branch o “Res_li.med”, opened “0”, Right Click it and Selected “Deflected Shape”. Te maximum deflection that Salome-Meca was showing was 33.7098mm.

2

Ten John opened result_ SIEQ_NOEU branch, opened “0”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “VMIS” in “Scalar Mode”. Click “OK”

— 104 —


#

Description

Figure

Te final result looks like figure shown below. 3 VMIS stresses are rom 0 to 492.556 MPa.

Now let’s check the results o Non-Linear Analysis and compare them with Linear Analysis. 4

5

John opened result_DEPL branch o “Res_nl.med”, opened “1”, Right Click it and Selected “Deflected Shape”. Te maximum deflection that Salome-Meca was showing was 37.1664mm which compared to Linear Analysis o 33.7098mm is close.

Ten John opened “2.1”, Right Click it and Selected “Deflected Shape”. Te maximum deflection that Salome-Meca was showing was 3.61039mm. Tis is the deflection that will be seen in the beam afer the load has been removed. Te pipe guide has yielded and the residual deflection in it is 3.61039mm.

— 105 —


#

Description

Figure

Now let’s check the stresses or Non Linear Analysis. Ten John opened result_SIEQ_NOEU branch, opened “1.0”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “VMIS” in “Scalar Mode”. 6

Click “OK”. Te final result looks like figure shown below. VMIS stresses are rom 0 to 409.793 MPa compared to 492.556 MPa in Linear Analysis.

Ten John opened result_SIEQ_NOEU branch, opened “2.1”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “VMIS” in “Scalar Mode”. Click “OK”. 7

Te final result looks like figure shown below. VMIS stresses are rom 0 to 158.953 MPa. Tis is the residual stress lef in the guide afer the load is removed.

— 106 —


#

Description

Figure

John said that by conducting Non-Linear analysis, it becomes easy to find out whether the entire geometry has yielded or not and what will be the residual stress lef in the geometry afer the load is removed. John urther told Esha that, she needs to be cautious and not use the residual stress as true stress as the material property used was not true and an approximation was made afer the yield strength. o get better results o the deormed shape and residual stress, John encouraged Esha to conduct the analysis with true Stress-Strain curve o Carbon steel.

— 107 —



How to define Yield stress o a material in command file

▶

How to define stepping unction or Non-Linear analysis in command file

▶

How to define Non-Linear Analysis in command file

▶

What to check i the analysis has errors.

Endnotes 1

Remember that Force on Face is Force / Area o Face. In our case it becomes 2000 / (100 x 10) = 2

2

ASK complaints i the path where you want to save the file has Spaces. I you get messages o that sort, ignore them.

3

Giving this Base Path makes writing o the file names easy, as you do not need to write the whole path o the file. You just need to state which file you want to use.

4

Alternatively just Right Click in the Name ext box and Select “Deault Value” and the name will be filled. It might not be the name that you have or the study, so be cautious and make sure the name is correct.

— 108 —

Non-Linear Material – Real Curve FE Analysis

Chapter 4b - Case 15b Non-Linear Material – Real Curve FE Analysis Esha was getting happy and impatient, seeing this John asked Esha what was on her mind. Esha told John that ever since he started Non-Linear Material analysis, she wanted him to show her how to perorm FE analysis with Real Material Curve. John said that, it was the exact same topic he was going to discuss next.

— 109 —


Step 1: Purpose o the FE Analysis / Description o the problem Te geometry that will be analysed is exactly same as previous Chapter with the only difference that the Material Stress-Strain curve will be added. Te geometry, material properties and loading or this study are noted below. For this study we will use 3 Dimensional model with Non-Linear Material Real Curve and perorm a Non-Linear Static FE analysis. Material Properties o Carbon Steel used in this study is given below.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Pipe Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 500mm Material Properties o the Pipe Guide are as ollows Material Name: SA 1548 Gr P430 Young’s Modulus: 2.0e5 MPa Poisson’s Ratio: 0.3 Stress Strain Curve Data

Stress 200 205 210 215 220 225 250 275 300 325 350 375 400 430

Strain 0.00100 0.00103 0.00106 0.00109 0.00113 0.00116 0.00143 0.00202 0.00356 0.00805 0.01933 0.03347 0.04735 0.06908

— 110 —


Force applied to this plate: 2000N (2kN)

Step 3: Model Geometry Modelling o the Geometry is exactly same as the previous chapter so it won’t be repeated here.

Step 4: Meshing Geometry Meshing o the Geometry is exactly same as the previous chapter so it won’t be repeated here.

Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient We will make changes to the .comm file rom previous case. Copy the file “Case15.comm” and save it to another older as “Case15b.comm”. Te entire .comm file is shown below. Comments related to Efficient sofware has been removed rom the comm file or easy reading. Important changes or making this comm file suitable or Non-Linear analysis with Real Curve are highlighted in RED colour. Comments are marked in GREEN or easy reerence. Here only Non-Linear analysis will be run, so any reerence to Linear analysis, as carried out in previous Case, has been removed.

— 111 —


Following is the list o changes that will be perormed on the comm file: 1. Add Curve or Stress Strain Curve 2. Add the Stress Strain curve to non-linear material 3. Modiy the SA_NON_LINE so that it considers Stress Strain Curve

#U4.11.01 DEBUT();



#U4.43.01 ####We need to store the Stress and Strain Data in a Function ####Note that Point 0,0 (Starting of curve) should not be specied ####We want Linear Interpolation between the points that we specied ####We want Linear curve from point 0, 0 to the rst point ####We want the curve to remain constant after the last value. s1548430=DEFI_FONCTION(NOM_PARA=’EPSI’, NOM_RESU=’SIGMA’, VALE=(0.00100, 200, 0.00103, 205, 0.00106, 210, 0.00109, 215, 0.00113, 220, 0.00116, 225, 0.00143, 250, 0.00202, 275,

— 112 —


0.00356, 300, 0.00805, 325, 0.01933, 350, 0.03347, 375, 0.04735, 400, 0.06908, 430,),

INTERPOL=’LIN’,

PROL_DROITE=’LINEAIRE’,

PROL_GAUCHE=’CONSTANT’, );

CS=DEFI_MATERIAU(ELAS=_F(E=2.0e5, NU=0.3, RHO=7.8e-9,), TRACTION=_F(SIGM=s1548430,),);


#U4.44.01 Fix=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix’,DX=0,DY=0,DZ=0,),);

#U4.44.01 ####Force on Face will be increased from 0 to Full Load in time 0 to 1 #### Force on Face will be kept constant at Full Load from time 1 to 1.1 #### Force on Face will be reduced from Full Load to 0 in time 1.1 to 2.1 ####

Load1 is the ramp function for Force on Face “Load”

Load=AFFE_CHAR_MECA(MODELE=model, FORCE_FACE=(_F(GROUP_MA=’Load’, FZ = -2,),),); Load1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(0.0,0.0,1.0,1.0,1.1,1.0,2.1,0.0),);

####The load increment is done in steps of 0.1 (PAS=0.1) step1=DEFI_LIST_REEL(DEBUT=0.0, INTERVALLE=_F(JUSQU_A=2.1, PAS=0.1,),); step=DEFI_LIST_INST(DEFI_LIST=_F(METHODE=’MANUEL’, LIST_INST=step1,),);

— 113 —


####Non-Linear Calculations are carried out and stored as res_nl ####Refer to U4.51.11 for COMP_INCR ####RELATION=’VMIS_ISOT_TRAC’ is used when Stress Strain material curve is dened res_nl=STAT_NON_LINE(MODELE=model, CHAM_MATER=material, EXCIT=(_F(CHARGE=Fix,), _F(CHARGE=Load, FONC_MULT=Load1,),), COMP_INCR=_F(RELATION=’VMIS_ISOT_TRAC’, DEFORMATION=’SIMO_MIEHE’, TOUT=’OUI’,), INCREMENT=_F(LIST_INST=step,), NEWTON=_F(REAC_INCR=1, MATRICE=’TANGENTE’, REAC_ITER=1,),

CONVERGENCE=_F(ITER_GLOB_MAXI=10,), );

res_nl=CALC_CHAMP(reuse=res_nl, RESULTAT=res_nl, CONTRAINTE=(‘SIGM_ELNO’,’SIGM_NOEU’,), CRITERES=(‘SIEQ_ELNO’,’SIEQ_NOEU’,), FORCE=(‘REAC_NODA’,),); #U4.91.01 ####We will store the results for Non-Linear calculation in a MED le as well ####Logical Unite for this MED le is “81” which will be used in Aster IMPR_RESU(FORMAT=’MED’, UNITE=80, RESU=_F(MAILLAGE=mesh, RESULTAT=res_nl, NOM_CHAM=(‘DEPL’, ‘SIEQ_NOEU’,),),); #U4.11.02 FIN();

Tis completes the steps to generate .comm file, now we want to generate Aster study case using ASK.

— 114 —


Step 10: Run the analysis As the calculation is same as previous Case, we will re-trace the steps. Tis time we will use Aster study case instead o ASK In Salome-Meca, start Aster Module and then click Aster -> Add study case #

Description

1

When Study case definition window opens, it should look similar to the adjacent figure.

Figure

Click “OK”.

Right Click “nonlinear” node in Aster tree -> Run 2 I everything goes well, study will complete with Post Pro module shown.


Description

Figure

1

John opened res_nl_DEPL branch, opened “1.”, Right Click it and Selected “Deflected Shape”. Te maximum deflection that Salome-Meca was showing was 46.4963mm.

— 115 —


#

Description

Figure

2

John opened res_nl_DEPL branch, opened “2.1”, Right Click it and Selected “Deflected Shape”. Te maximum deflection that Salome-Meca was showing was 11.3528mm. Tis is the residual deflection lef afer the load has been removed.

Ten John opened res_nl_SIEQ_NOEU branch, opened “1.”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “VMIS” in “Scalar Mode”. 3

Click “OK” Te final result looks like figure shown below. VMIS stresses are rom 0 to 421.197 MPa.

Now let’s check the results o residual stresses. 4

Ten John opened res_nl_SIEQ_NOEU branch, opened “2.1”, Right Click it and Selected “Scalar Map”. Ten in the window that opens, Select “VMIS” in “Scalar Mode”. Te residual stress in the Guide is 164.58 MPa.

— 116 —


#

Description

Figure

John said that by conducting Non-Linear analysis with Stress Strain curve, it becomes easy to find out the whether the entire geometry has yielded or not and what will be the residual stress lef in the geometry afer the load is removed.


How to define a Stress Strain curve data o a material in .comm file

▶

How to define Non-Linear Analysis in .comm file

▶

What to check i the analysis has errors.

— 117 —


Notes:

— 118 —

Non-Linear FE Analysis with Contact

Chapter 5 - Case 16 Non-Linear FE Analysis with Contact Afer completing Non-Linear Material FE analysis, Esha was very keen to understand how to model and analyse Contact in FE Analysis using Salome and Code_Aster. Esha said that the deflection o the Guide in previous analysis was too high and that client wanted to reduce the deflection but thickening o the guide was not an option, nor was the option open to change the material. John said that in that case the analysis we will look at is Non-Linear FE analysis with Contact between two parts.

— 119 —


Step 1: Purpose o the FE Analysis / Description o the problem Te geometry that will be analysed is same as previous Case o an elongated Pipe Guide which had to be designed due to constraints in space around the piping. o reduce the deflection another L shaped Guide is introduced which supports the Pipe Guide at 400mm with a gap between them o 3mm.

Te geometry, material properties and loading or this study are noted below. For this study we will use 3 Dimensional model with Non-Linear Contact and perorm a Non-Linear Static FE analysis.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Pipe Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 500mm Dimensions o the L shaped Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 400mm Protrusion o the Leg: 50mm Gap between Pipe Guide and L shaped Guide is 3mm

— 120 —


Material Properties o the Pipe Guide and L shaped Guide are as ollows Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Force applied to the Pipe Guide: 2000N (2kN)

Step 3: Model Geometry John asked Esha to generate the Geometry or both Pipe Guide and L shaped Guide and Mesh them. He asked Esha to save two separate MED files or Pipe Guide and L shaped Guide. Esha started Salome-Meca and created a new study. She started Geometry Module and began creating model o Pipe guide. #

Description

Figure

For generating Pipe Guide model, Esha started with the use o Primitive shape. Click New Entity -> Primitives -> Box and enter the values as shown in the figure and change its Name to “Guide”. Click on “Apply”. 1

Create two more Boxes: Name: Box_1 Dx: 400, Dy: 100, Dz: 10 Click “Apply” Name: Box_2 Dx: 10, Dy: 100, Dz: 50 Click “Apply and Close”

— 121 —


#

Description

Figure

Next we need to translate Box_2 by 400mm in X direction. Click Operations -> ransormation -> ranslation 2

Enter inormation as shown in adjacent figure. Make sure you Untick “Create a copy” Click “Apply and Close”

Next we will Fuse Box_1 and Box_2. Click Operations -> Boolean -> Fuse 3 Change the Name to “LGuide” and Select “Box_1” or Object 1 and “Box_2” or Object 2. Click “Apply and Close”

— 122 —


#

Description

Figure

Next we need to translate LGuide by 53mm in negative Z direction. (50mm or the protrusion o “L” and 3mm or the gap between Pipe Guide and L shaped Guide) 4

Click Operations -> ransormation -> ranslation Enter inormation as shown in adjacent figure. Make sure you Untick “Create a copy” Click “Apply and Close”

5

Groups needs to be created on “Guide” and “LGuide” as shown in screenshot below.

— 123 —


#

Description

6

Right Click Guide -> Create Group and add Volume Group “vGuide” and Surace group o “Fix_Gui”, “Load” and “contactm”.

Figure

Right Click LGuide -> Create Group and add Volume Group “vLGuide” and Surace group o “Fix_LGui” and “contacts”.

7

Your Object Browser should look like adjacent figure.


— 124 —



Description

Select “Guide” Browser.

Figure

in

Object

Click Mesh -> Create Mesh.

1

In the dialogue box that pops up, Give it a Name “Guide”, Click “Assign a set o hypotheses” and Select “3D: Automatic etrahedralization”. In the window or Hypothesis Construction Click “Cancel” as we are going to define our own Hypothesis.

2

Click ab “1D” and Click on the Gear button next to Hypothesis. Select “Automatic Length” and enter “0.5” in the window that pops up. Click “OK” on Hypothesis Construction window and “Apply and Close” on Create Mesh window.

Right Click Guide -> Compute. 3

Final Mesh or Guide should look like adjacent figure.

— 125 —


#

4

Description

Figure

Right Click Guide -> Create Group rom Geometry and in the window that pops up Select “vGuide”, “Fix_Gui” “Load” and “contactm” rom Geometry. Click “Apply and Close”

5

Repeat same steps or “LGuide”

— 126 —


#

Description

6

Your Object Browser should now look like adjacent figure.

Figure

Right Click “Guide” -> Export -> MED. In the window that opens enter “Guide” or the File name and Click “Save” 7

By deault this file will be saved in the same location as the HDF file. Right Click “LGuide” -> Export -> MED.

8

In the window that opens enter “LGuide” or the File name and Click “Save” Tis concludes creating Mesh. Save the HDF file.

— 127 —


Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Esha handed the reins o the analysis to John or Non-Linear Contact FE analysis. John said that here we will make the comm file by using Efficient and then modiy it by making necessary changes or running Non-Linear analysis. #

Description

1

In Mesh ab, keep everything deault

Figure

In Analysis ab, select “Mechanical – 3D Assembly. Inormation about Assembly should be available now. 2

Enter “Guide” or Mesh Name and “20” or Number (LU) and Click “Add Mesh Name and No” Enter “LGuide” or Mesh Name and “21” or Number (LU) and Click “Add Mesh Name and No”

— 128 —


#

Description

3

Enter “contactm” or Master and “contacts” or Slave and Click “Add Master Slave Pair”

4

In Material ab, Enter the inormation as shown in the adjacent figure. Click “Add” material.

5

Figure

to

add

this

We don’t need to enter anything or Element ab

— 129 —


#

Description

Figure

In Boundary Condition(s) ab, Enter the inormation or restricting ace “Fix_Gui” in All three directions as shown in the figure. 6

Click on “Add” Enter “Fix_LGui” or “Boundary Condition Name” and “Is Assigned to” field and enter “0” or DX, DY and DZ. Click on “Add”.

Now we need to enter a Load o “2000N” in Z direction on Face “Load”.

7

Enter “Load” or Load Name, Select “Force on Face” or Load ype, Enter “Load” or Is Assigned to. Finally Enter “-2” or FZ. 1 Click “Add”. For this study we do not need to enter Stepping unction or Loads.

— 130 —


#

Description

Figure

Next we will add a step unction to “Loa “Load” d”..

8

On the right hand side, Enter “Load1” as Load Stepping Function Name, select “Load” as Load Name, keep Constant or Lef and Right side o Function. Enter 0,0,1,1 or the Load Step Pair which essentially means that at step 0 Load is 0 and at step 1 Full Load is applied.

9

For the Output type, Select “SIEQ_NOEU” as we want to get VonMises stresses on Nodes in MED file. Click Clic k “Add”

— 131 —


#

Description

Figure

Click “Save .comm file”. 10

Save it as “Case16.comm” in the location where you saved the study s tudy..

Te entire .comm file generated by by Efficient is shown below. below. Comments related to Efficient sofware has been removed rom the comm file or easy reading. Important changes or making this comm file suitable or NonLinear Contact analysis are highlighted in RED colour. Comments are marked in GREEN GREEN or or easy reerence. Followingg is the list o changes that will be perormed on the comm file: Followin 1. Modiy Stepping uncti unction on or Load 2. Add Contact inormation 3. Add Stepping unct unction ion or Non-Linear Analysis 4. Add inormation to Perorm analysis or Non-Linear setup 5. Save MED file with Non-Linear Contact analysis results

#U4.11.01 DEBUT();

#U4.21.01 Guide=LIRE_MAILLAGE(UNITE=20, FORMAT=’MED’,);

LGuide=LIRE_MAILLAGE(UNITE=21, FORMAT=’MED’,);

mesh=ASSE_MAILLAGE(MAILLAGE_1=Guide, MAILLAGE_2=LGuide, OPERATION=’SUPERPOSE’,);

— 132 —



#U4.43.01 CS=DEFI_MATERIAU(ELAS=_F(E=2.1e5, NU=0.3, RHO=7.8e-9,),);


#U4.44.01 Fix_Gui=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix_Gui’,DX=0,DY=0,DZ=0,),);

Fix_LGui=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix_LGui’,DX=0,DY=0,DZ=0,),);

####We don’t need to combine the meshes here so the entire block is commented out #combine=AFFE_CHAR_MECA(MODEL=model, #

LIAISON_MAIL=(_F(GROUP_MA_MAIT=’contactm’,

#

GROUP_MA_ESCL=’contacts’,

#

TYPE_RACCORD=’MASSIF’,),

#

),);

####combine command nishes here AND so does our comment :) ####We need a CONTACT denition in the comm le contact=DEFI_CONTACT(MODELE=model, FORMULATION=’DISCRETE’, ZONE=_F(GROUP_MA_MAIT=’contactm’, GROUP_MA_ESCL=’contacts’,), );

— 133 —


#U4.44.01 Load=AFFE_CHAR_MECA(MODELE=model, FORCE_FACE=(_F(GROUP_MA=’Load’, FZ = -2,),),);

#U4.31.02 Load1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(0,0,1,1,), PROL_GAUCHE=’CONSTANT’, PROL_DROITE=’CONSTANT’, ); ####We want the stepping function to have a step of 0.1 list=DEFI_LIST_REEL(DEBUT=0, INTERVALLE=_F(JUSQU_A=1, PAS=0.1, PAS=0.1,),); ),);

####This calculation is Non-Linear Static Analysis so we will do our changes here too. ####

Change MECA_STATIQUE to STAT_NON_LINE

####

Comment our _F(CHARGE=combine,)

####

Add CONTACT=contact,

####

Add COMP_INCR to show what type of increment will happen.

####

We are using

Elastic Material and Small deformation.

result= STAT_NON_LINE STAT_NON_LINE(MODELE=model, (MODELE=model, CHAM_MATER=material,

EXCIT=(_F(CHARGE=Fix_Gui,), _F(CHARGE=Fix_LGui,), #_F(CHARGE=combine,), _F(CHARGE=Load, FONC_MULT=Load1,), ),

CONTACT=contact, COMP_INCR=_F(RELATION=’ELAS’, DEFORMATION=’PETIT’, TOUT=’OUI’,), INCREMENT=_F(LIST_INST=list, INCREMENT=_F( LIST_INST=list,), NEWTON=_F(REAC_INCR=1, MATRICE=’TANGENTE’, REAC_ITER=1,), CONVERGENCE=_F(ITER_GLOB_MAXI=10,),); CONVERGENCE=_F(ITER_GLOB_MAXI=10,), );

— 134 —



#U4.91.01 ####We are outputting the result in 1 mesh so comment out RESTREINT IMPR_RESU(FORMAT=’MED’, UNITE=80, #RESTREINT=_F(GROUP_MA=’Guide’,), RESU=_F(MAILLAGE=mesh, RESULTAT=result, NOM_CHAM=(‘DEPL’, ‘SIEQ_NOEU’,),),);

####We don’t need the output in two separate meshes so we will comment out below IMPR_RESU #IMPR_RESU(FORMAT=’MED’, #

UNITE=81,

#

RESTREINT=_F(GROUP_MA=’LGuide’,),

#

RESU=_F(MAILLAGE=mesh,

#

RESULTAT=result,

#

NOM_CHAM=(‘DEPL’, ‘SIEQ_NOEU’,),),);

####End of Comment

#U4.11.02 FIN();

Tis completes the steps to generate .comm file, now we want to generate Aster study case using ASK.

— 135 —


Step 10: Run the analysis John activated Aster Module in Salome-Meca and then instead o a simple Aster study case he started ASK. In Salome-Meca, start Aster Module and then click Aster -> ools -> Run ASK #

Description

1

When ASK opens, it should look similar to the adjacent figure.

2

Figure

Click File -> Save, ASK will ask i you would like to Save the current environment. Click “YES”

Ten it will show you a dialogue box o where do you want to save the file. 3

Navigate to the location where you want to save the file and give it a meaningul name. Here we have used “Case16”. Click “Ok”.2

— 136 —


#

Description

Figure

Afer that you need to give ASK a Base path rom where it will be able to get MED files and where it should save the results. 3 4

Click on the Folder Icon adjacent to the ext Box adjacent to “Base Folder” and navigate to the place where we saved the .astk file. Click “Ok”.

5

Click on the New File Icon in ASK main window as highlighted in the adjacent figure and a new line will be added to ASK.

In the new line that is created we need to speciy which file we want to add to this study. You can select what type o file you want to add to the study by clicking on the selection box under “ype” You don’t need to change the Server name as most o the analysis will be run on your Local computer. 6

In the name field you write the names o the files. For example the ype o file is “comm” so we write the name o the file “Assembly.comm” in the Name field. “LU” is the unit o file (Remember UNIE=80) “D” i ticked itmeans that the file is an Input file (.comm and MED files) “R” i ticked means that the file is an Output file (Message, Error, MED files) “C” i ticked means that the file will be Compressed (to save space)

— 137 —


#

Description

7

For our study, we will write the name “Case16.comm” file as shown in adjacent figure.4

Figure

Click on the new File icon. Change the ype to “mail” and enter the Name “Guide.med” with a LU o “20”. 8 Click on the new File icon. Change the ype to “mail” and enter the Name “LGuide.med” with a LU o “21”.

9

Click on the new File icon. Change the ype to “mess” (Message file) and enter the Name “Case16.mess”.

— 138 —


#

Description

10

Click on the new File icon. Change the ype to “resu” (Result file – ext file) and enter the Name “Case16.resu”.

11

Click on the new File icon. Change the ype to “erre” (Error file) and enter the Name “Case16.erre”.

12

Click on the new File icon. Change the ype to “rmed” (Result MED file) and enter the Name “Case16resu.med” with a LU o “80”. (Tis is the result o Linear Analysis)

Figure

— 139 —


#

Description

Figure

As we are used to increasing the Memory and time in Aster in Salome-Meca Wizard, let’s do it here as well. 13

Increase the memory to “2048” and time to “15:15:00”. Click on interactive ollow-up i you would like to see what is happening behind the scenes and at what step Code_Aster is.

14

Finally Click File -> Save to save the ASK file and then Click on “Run” (not “run” as that is or selecting whether you want to Run the analysis or Debug it.

15

I everything goes well, you will be able to see all the result files that we had asked Code_ Aster to generate viz. Message file, Result file etc. along with “Case16resu.med” file in the older.

— 140 —



Description

Figure

Click File -> Import -> MED file. A new window opens. John selected “Case16resu.med” file. 1

2

John opened result_DEPL branch o “Case16resu.med”, opened “1.0”, Right Click it and Selected “Deflected Shape”. Use Scale Factor o “1” and ick “Magnitude Colouring”. Te maximum deflection that Salome-Meca was showing was 16.3619mm which compared to only Guide o 33.7098mm is nearly hal.

Here interesting observation is that both Pipe Guide and L shaped Guide have deormed and on zooming in at the contact surace it can be seen that both meshes are in contact and are not intruding into the geometry.

Esha asked, but how can we know when the contact occurred and whether the gap was resolved properly or not. 3 John said that, or this you need to look at all the time steps starting rom 0.1 to figure out when the contact occurred.

— 141 —


#

Description

Figure

4

John opened “0.1”, Right Click it and Selected “Deflected Shape”. Use Scale Factor o “1” and ick “Magnitude Colouring”. Te maximum deflection that Salome-Meca was showing or Pipe Guide was 2.82817mm and that or L shaped Guide is 0mm. Tis suggests that at this point the load is taken only by the Pipe Guide and that L shaped Guide is not in contact and is not taking load.

5

John opened “0.2”, Right Click it and Selected “Deflected Shape”. Use Scale Factor o “1” and ick “Magnitude Colouring”. Te maximum deflection that Salome-Meca was showing or Pipe Guide was 4.89187mm and that or L shaped Guide is close to 1mm as the colour o L shaped Guide has changed rom dark blue to light blue. Tis suggests that at this point contact has just happened and the load sharing is starting.

— 142 —


#

Description

Figure

o have a look at how the animation o the deormation looks like, Right Click “result_ DEPL” -> Deormed Shape. 6

Enter “1” as the Scale Factor and “ick” Magnitude Coloring Click View -> Windows -> Slider and start the animation.

Have a look at VonMises Stresses and you will find a similar pattern o load sharing. 7 Te maximum VonMises stress is 262.030MPa which is lower than Yield strength o material.

— 143 —


#

Description

Figure


How to define contact in .comm file

▶

How to define stepping unction or Non-Linear analysis in .comm file

▶

How to define Non-Linear Contact Analysis in .comm file

Endnotes 1

Remember that Force on Face is Force / Area o Face. In our case it becomes 2000 / (100 x 10) = 2

2

ASK complaints i the path where you want to save the file has Spaces. I you get messages o that sort, ignore them.

3

Giving this Base Path makes writing o the file names easy, as you do not need to write the whole path o the file. You just need to state which file you want to use.

4

Alternatively just Right Click in the Name ext box and Select “Deault Value” and the name will be filled. It might not be the name that you have or the study, so be cautious and make sure the name is correct.

— 144 —

Non-Linear FE Analysis with Contact and Non-Linear Material

Chapter 5b - Case 16b Non-Linear FE Analysis with Contact and Non-Linear Material John told Esha that next he is going to show her how to carry out the same analysis o Contact with Non-Linear Material.

— 145 —


Step 1: Purpose o the FE Analysis / Description o the problem Te geometry that will be analysed is same as previous Chapter o an elongated Pipe Guide with L shaped Guide and having a gap between them o 3mm.

Te geometry, material properties and loading or this study are noted below. For this study we will use 3 Dimensional model with Non-Linear Contact and Non-Linear Material and perorm a Non-Linear Static FE analysis.

Step 2: Input values or the FE analysis Input values or the Analysis are same as previous chapter and are shown below. Te only difference is that we are using Non-Linear Material Carbon Steel with Yield Strength o 300MPa. Dimensions o the Pipe Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 500mm Dimensions o the L shaped Guide are as ollows Width o the Plate: 100mm Tickness o the Plate: 10mm Height o the Plate: 400mm Protrusion o the Leg: 50mm

— 146 —


Material Properties o the Pipe Guide and L shaped Guide are as ollows Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Yield Strength: 300 MPa Force applied to the Pipe Guide: 2000N (2kN)

Step 3: Model Geometry Modelling o the Geometry is exactly same as the previous chapter so it won’t be repeated here.

Step 4: Meshing Geometry Meshing o the Geometry is exactly same as the previous chapter so it won’t be repeated here.

Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient We will make changes to the command file rom previous case. Copy the file “Case16.comm” and save it to another older as “Case16b.comm”. Te entire command file is shown below. Comments related to Efficient sofware has been removed rom the comm file or easy reading. Important changes or making this comm file suitable or Non-Linear Contact analysis with Non-Linear Material are highlighted in RED colour. Comments are marked in GREEN or easy reerence. Following is the list o changes that will be perormed on the comm file: 1. Modiy Stepping unction or Load 2. Add Contact inormation 3. Add Stepping unction or Non-Linear Analysis 4. Add inormation to Perorm analysis or Non-Linear setup 5. Save MED file with Non-Linear Contact analysis results

#U4.11.01 DEBUT();

#U4.21.01 Guide=LIRE_MAILLAGE(UNITE=20, FORMAT=’MED’,);

— 147 —


LGuide=LIRE_MAILLAGE(UNITE=21, FORMAT=’MED’,);

mesh=ASSE_MAILLAGE(MAILLAGE_1=Guide, MAILLAGE_2=LGuide, OPERATION=’SUPERPOSE’,);


#U4.43.01 CS=DEFI_MATERIAU(ELAS=_F(E=2.1e5, NU=0.3, RHO=7.8e-9,), ECRO_LINE=_F(D_SIGM_EPSI=0, SY=300.0,),);


#U4.44.01 Fix_Gui=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix_Gui’,DX=0,DY=0,DZ=0,),);

Fix_LGui=AFFE_CHAR_MECA(MODELE=model, DDL_IMPO=_F(GROUP_MA=’Fix_LGui’,DX=0,DY=0,DZ=0,),);

contact=DEFI_CONTACT(MODELE=model, FORMULATION=’DISCRETE’, ZONE=_F(GROUP_MA_MAIT=’contactm’, GROUP_MA_ESCL=’contacts’,), );

#U4.44.01 Load=AFFE_CHAR_MECA(MODELE=model, FORCE_FACE=(_F(GROUP_MA=’Load’, FZ = -2,),),);

— 148 —


#U4.31.02 Load1=DEFI_FONCTION(NOM_PARA=’INST’, VALE=(0,0,1,1,),); ####We want the stepping function to have a step of 0.1 step1=DEFI_LIST_REEL(DEBUT=0, INTERVALLE=_F(JUSQU_A=1.0, PAS=0.1,),); step=DEFI_LIST_INST(DEFI_LIST=_F(METHODE=’MANUEL’, LIST_INST=step1,),);

####This calculation is Non-Linear Static Analysis so we will do our changes here. ####

Add COMP_INCR to show what type of increment will happen.

####

We are using

Non-Linear Elastic Material and SIMO_MIEHE deformation.

result= STAT_NON_LINE(MODELE=model, CHAM_MATER=material,

EXCIT=(_F(CHARGE=Fix_Gui,),

_F(CHARGE=Fix_LGui,), _F(CHARGE=Load, FONC_MULT=Load1,), ),

CONTACT=contact,

COMP_INCR=_F(RELATION=’VMIS_ISOT_LINE’, DEFORMATION=’SIMO_MIEHE’, TOUT=’OUI’,),

INCREMENT=_F(LIST_INST=step,), NEWTON=_F(REAC_INCR=1, MATRICE=’TANGENTE’, REAC_ITER=1,), CONVERGENCE=_F(ITER_GLOB_MAXI=10,),);


— 149 —


#U4.91.01 ####We are outputting the result in 1 mesh IMPR_RESU(FORMAT=’MED’, UNITE=80, RESU=_F(MAILLAGE=mesh, RESULTAT=result, NOM_CHAM=(‘DEPL’, ‘SIEQ_NOEU’,),),); #U4.11.02 FIN();

Tis completes the steps to generate command file, now we want to generate Aster study case using ASK.

Step 10: Run the analysis Tis study is the same as previous one so the steps remains same. John activated Aster Module in Salome-Meca and then instead o a simple Aster study case he started ASK. In Salome-Meca, start Aster Module and then click Aster -> ools -> Run ASK We will not show the ull steps, just the final screen shot o how ASK looks like is shown here. #

Description

1

Note that name o the files have been changed to Case16b.

Figure

Finally Click File -> Save to save the ASK file and then Click on “Run” (not “run” as that is or selecting whether you want to Run the analysis or Debug it. 2 I everything goes well, you will be able to see all the result files that we had asked Code_Aster to generate viz. Message file, Result file etc. along with “Case16bresu.med” file in the older.

— 150 —



Description

Figure

Click File -> Import -> MED file. A new window opens. John selected “Case16bresu.med” file. 1

John opened result_DEPL branch o “Case16bresu.med”, opened “1.0”, Right Click it and Selected “Deflected Shape”. Use Scale Factor o “1” and ick “Magnitude Colouring”. Te maximum deflection that Salome-Meca was showing was 16.4010mm.

Have a look at VonMises Stresses and you will find a similar pattern o load sharing. 2 Te maximum VonMises stress is 262.718MPa which is lower than Yield strength o material.

— 151 —



How to define contact and Non-Linear material in command file

▶

How to define stepping unction or Non-Linear analysis in command file

▶

How to define Non-Linear Contact and Non-Linear Material Analysis in command file

— 152 —

FE Analysis of 3D Plate for Mode Shapes

Chapter 6 - Case 17 FE Analysis o 3D Plate or Mode Shapes Esha told John that there are instances when they have been asked to provide Modes o Vibration o an object. Tese mode shapes are then used or other calculations. Esha had seen a Wizard in Aster Module o Salome-Meca but when she tried it, there was no provision or 1D analysis. So next Esha wanted to learn was, how to find out Mode Shapes (Natural Frequency) o 1D objects. John told Esha that first he wants her to show him what she does to generate Mode Shapes o a 3D plate using Wizard. Once that is done, John will extend this urther and show how to get mode shapes rom a 2D and 1D analysis.

— 153 —


Step 1: Purpose o the FE Analysis / Description o the problem John told Esha that we will take a very simple example o a 3D plate that is fixed at one end. Te geometry and material properties or this study are noted below. For this study we will use 3 Dimensional model and perorm a Modal FE analysis.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the 3D plate are as ollows Width o the Plate: 50mm Tickness o the Plate: 10mm Height o the Plate: 500mm Material Properties o the Plate are as ollows Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Density o Material: 7800 kg/m3 John asked Esha to do a manual calculation or the Natural Frequency o a Beam so that the results can be verified.

— 154 —


Esha summarised that the natural requencies that the beam should have are 33.5656, 209.785, 588.3517, 1153.8178 and 1907.1368 Hz based on her calculation.

— 155 —


Step 3: Model Geometry John asked Esha to carry out the analysis with the given parameters. #

Description

Figure

For generating 3D Plate model, Esha started with the use o Primitive shape. 1

Click New Entity -> Primitives -> Box and enter the values as shown in the figure and change its Name to “Plate”. Click on “Apply and Close”.

— 156 —


#

Description

Figure

Create Face groups or “Fix” boundary condition on the ace that lies on Plane YOZ. 2

Tinking orward Esha decided that she will need a Sub Mesh or the thickness with density o 5 and so she made an Edge group “Sub_5” o one o the 10mm Edge on the thickness o the Plate.


— 157 —



Description

Figure

Click Mesh -> Create Mesh. In the dialogue box that pops up, Click “Assign a set o hypotheses” and Select “3D: Automatic Hexahedralization”. 1

In the window or Hypotheses Construction enter “50” or Number o Segments and Click “OK”. Click “Apply and Close” in Create Mesh window. Mesh density o 50 or the thickness is an overkill. As per pre-planning Esha specified a Sub-Mesh with number o segments 5.

2

Right-Click “Mesh_1” and in the Sub Mesh window select “Sub_5” or Geometry. Select “Wire discretisation” or Algorithm and “Nb. Segments” or Hypothesis. Enter “5” or Number o Segments Click “OK”

— 158 —


#

Description

Figure

Select “Propagation o 1D Hyp. On Opposite Edges” or Add. Hypothesis. 3

Sub Mesh window looks like adjacent figure. Click “Apply and Close”


Mesh_1

->


— 159 —


#

5

Description

Figure

Right Click Mesh -> Create Group rom Geometry and in the window that pops up Select “Fix” rom Geometry. Click “Apply and Close”

6


— 160 —


Step 5, 6, 7, 8 and 9: Creating command file by Wizard Esha knew that next step is to use Aster wizard to generate the study or Modal Analysis. She started Aster Module. Click Aster -> Wizards -> Modal Analysis #

Description

1

In the first ab keep deault “3D” selected.

Figure

Click “Next”.

2

In Modal Analysis ab, Select “Mesh_1” or Mesh and make sure that “Use geometrical groups” is selected.

— 161 —


#

Description

Figure

In Material Properties, Enter the inormation as shown in the adjacent figure. 3

4

Remember that deault units are mm or Length, MPa or Pressure/Stress/Strength, tonne/mm^3 or Density.

For Boundary Condition, Select Fix and enter 0 or DX, DY and DZ.

— 162 —


#

Description

5

Enter “10” or the Number o Modes as we want to find out the first 10 Natural requencies o the Plate.

Figure

Save the file in the location where you saved the study as “Case17.comm”.

6

Tis completes the steps to generate command file and Aster study.

— 163 —


Step 10: Run the analysis Right Click on “modal_analysis” in Aster branch and Select “Run”. I the analysis runs successully a Post-Pro branch will be added to the Object Browser.

Step 11: Post Processing o the Results Esha enabled “Post-Pro” module. #

Description

1

Esha opened all the branches that were ound in Post-Pro module and the results are as shown in adjacent figure.

2

3

Figure

Afer having a look at the results and comparing it with the hand calculations she did earlier, she was conused as there were several requencies that were present in the result obtained rom Code_Aster but not in her calculation. She decided to ask John about this. John had a look at the results obtained rom both sources and said that the first natural requency obtained rom both hand calculation and Code_Aster is within the limits o calculation. He urther commented that there was something that Esha had orgotten completely while doing her hand calculation. A plate can vibrate on both axis and the calculation that Esha did only considered Moment o Inertia on one axis. John asked Esha to do her calculation again calculate requencies considering Moment o Inertia rom both axis. Esha quickly did the calculation and showed her result to John.

— 164 —


#

Description

Figure

— 165 —


#

Description

Figure

Esha decided to check the Deflected shapes o the Modes o Vibration and compare it with hand calculation. 4

Right Click “39.7378” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring.

5

Enable side view to see deflection as shown in adjacent figure. Right Click “168.281” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring.

6

Enable top view to see deflection as shown in adjacent figure. Right Click “248.68” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable side view to see deflection as shown in adjacent figure.

7

Right Click “607.137” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable Iso view to see deflection as shown in adjacent figure.

— 166 —


#

Description

8


9


10

Enable top view to see deflection as shown in adjacent figure. Right Click “1360.74” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring.

Figure

Enable side view to see deflection as shown in adjacent figure.

11


— 167 —


#

Description

Figure

12

Right Click “2245.56” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable side view to see deflection as shown in adjacent figure.

13


Esha understood that some o the Mode shapes were or deflection in Primary Axis o the beam, some rom the Secondary Axis o the beam and some rom orsional Axis. 14

But she was not able to understand the mode shape with Frequency 2601.12Hz. She asked John about it and John asked Esha to create Sweep by Right Clicking “De.Shape:9” and clicking on “Sweep”.

When Esha saw the animation she realised that this is the requency when the beam is purely in tension. John asked Esha to summarise her results in a table. Esha made a table which compared the natural requencies calculated by Hand and that which was calculated by Code_Aster in a table. Natural requency

Hand Calculation Primary Axis (Hz)

F1

33.5656

F2 F3 orsion Axis F4

39.7378 167.828

209.785

168.281 248.68

-NA588.3517

F5 F6

– Hand Calculation – Code_Aster (Hz) Secondary Axis (Hz)

1048.9252 1153.8178

607.137 695.408 1009.86 1360.74

— 168 —


Natural requency

orsion Axis F7 Linear Expansion F8



-NA-

1833.53 2245.56

-NA2941.7585

2601.12

1907.1368

F9

5769.0888

F10

9535.6839

John commended Esha to carry out the calculation or Mode shapes all by hersel and comparing the result with Hand Calculation. He told Esha that next he will show her how to modiy the command file that was automatically generated by Aster Wizard to conduct 1D and 2D Mode shape analysis.


How to use Aster Wizard to conduct Mode Shape FE Analysis

▶

How to compare the results o hand calculation with that o Code_Aster.

— 169 —


Notes:

— 170 —

FE Analysis of 1D Beam for Mode Shapes

Chapter 7 - Case 18 FE Analysis o 1D Beam or Mode Shapes Esha knew what John was going to show her next. Esha asked John i he could use the same parameters that they used or 3D Mode shape analysis or the 1D analysis that he was going to show her. John started laughing and said that it was exactly the same thing that he was going to do so that they can compare the results.

— 171 —


Step 1: Purpose o the FE Analysis / Description o the problem John told Esha that we will take a very simple example o a 1D beam that is fixed at one end. Te geometry and material properties or this study are noted below. For this study we will use 1 Dimensional model and perorm a Modal FE analysis by editing the command file.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Plate are as ollows Width o the Plate: 50mm Tickness o the Plate: 10mm Height o the Plate: 500mm Material Properties o the Plate are as ollows Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Density o Material: 7800 kg/m3 Manual calculation or the natural requency was conducted in previous chapter. It is provided here or easy reerence.

— 172 —


Summary o the natural requencies o the beam: 33.5656, 167.828, 209.785, 588.3517, 1048.9252, 1153.8178, 1907.1368, 2941.7585, 5769.0888 and 9535.6839 Hz.

— 173 —


Step 3: Model Geometry John asked Esha to generate the Geometry. #

Description

1

Click New Entity -> Basic -> Point and enter the values as shown in the figure and change its Name to “P1”. Click on “Apply and Close”.

Figure

Next we will create a Line joining two points. points. 2

Click New Entity -> Basic -> Line and select two Points, “O” and “P1” as shown in adjacent figure. Click on “Apply and Close”.

— 174 —


#

Description

Figure

Create Point groups or “Fix” boundary condition as shown in adjacen adjacentt figure. Select the Point at the Origin and add it. Click “Apply” 3 Create a Line group or “Guide” “Guide” to give beam properties in command file. Select the whole Line and add it. Click “Apply and Close”

Tis concludes Geometric modelling or this Analysis 4 Esha saved this file as “Case18.hd” “Case18.hd ” to a convenient location location

— 175 —


Step 4: Meshing Geometry Esha changed Geometry Module to Mesh Module and began creating mesh o the beam. #

Description

Figure

Click Mesh -> Create Mesh. In the dialogue box that pops up only 1D tab is enabled to enter values, Select “Wire Discretisation” or Algorithm. 1

2

Click on Gear button adjacent to Hypotheses and in the window or Hypotheses Construction enter “50” or Number o Segments and Click “OK”.

Mesh window adjacent figure.

looks

like

Click “Apply and Close”

— 176 —


#

Description

Right Click Compute. 3

4

Figure

Mesh_1

->

I the computation is successul it should look like adjacent figure.

Right Click Mesh -> Create Group rom Geometry and in the window that pops up Select “Fix” and “Guide” rom Geometry. Click “Apply and Close”

5

Tis co conc nclu lude dess cr crea eati ting ng Mes esh. h. Sa Save ve th thee HDF HDF fil file. e.

— 177 —


Step 5, 6, 7, 8 and 9: Modiying comm file created by Wizard For the next step, Esha handed the analysis to John to explain urther. John said that we will modiy the command file generated by the Wizard in previous chapter to make it suitable or 1D analysis. Copy “Case17.comm” and Paste it in the older or Case 18 as “Case18.comm” and ollow the instructions shown below. #

Description

1

First we need to change the Modelisation o the analysis rom “3D” to “POU_D_” as shown in adjacent figure.

Figure

— 178 —


#

Description

Figure

Next we need to speciy the dimensions o the Beam or the 1D analysis.

2

Enter the Beam definition as a Rectangle with width 50 and depth 10 as shown in adjacent figure. Give it a name “Guide”.

As 1D beam has 6 degrees o reedom compared to 3 degrees o reedom or nodes o a 3D geometry, we need to restrict rotations in 3 directions. 3

Change GROUP_MA=’Fix’, to GROUP_NO=’Fix’ Add DRX=0, DRY=0 and DRZ=0 as shown in adjacent figure.

— 179 —


#

Description

Figure

Next we need to add the Element definition to the calculation. 4 Add “CARA_ELEM=Guide,” to ASSEMBLAGE as shown in adjacent figure.

5

Tis completes steps to modiy command file. Next we will create Aster study.

Enable “Aster” module. Click Aster -> Add Study Case.

6

Enter “1DModeShapes” as Name, Select “Case18.comm” or the command file and select “Mesh_1” rom the Object Browser. Keep everything else as shown in adjacent figure. Click “OK”

Tis completes the steps to create Aster study.

— 180 —


Step 10: Run the analysis Right Click on “1DModeShapes” in Aster branch and Select “Run”. Afer the analysis completed, “Post-Pro” module was added to the Object Browser. John said that this is the time to see the results.

Step 11: Post Processing o the Results John let Esha have a look at the results. Esha enabled “Post-Pro” module. #

Description

Figure

1


2

Esha compared the results with that obtained with hand calculation.

— 181 —


#

Description

Figure

Esha decided to check the Deflected shapes o the Modes o Vibration and compare it with hand calculation. 3


4


5

Enable top view to see deflection as shown in adjacent figure. Right Click “209.648” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring.

6

Enable side view to see deflection as shown in adjacent figure. Right Click “585.235” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable side view to see deflection as shown in adjacent figure.

— 182 —


#

Description

7

Right Click “590.02” -> Deormed Shape. Te deault value or Scale Factor was very high (6.6413e+12) and so Esha opened Scalar Bar tab and started to investigate. She ound out that each Scalar Mode had very low value except DRX as shown in adjacent figure.

Figure

She concluded that this mode shape is or orque. She accepted the deault or everything and enabled Iso view to visualise the deormation.

8

Right Click “996.827” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable top view to see deflection as shown in adjacent figure.

— 183 —


#

Description

9


Figure


10

Right Click “1770.64” -> Deormed Shape. Te deault value or Scale Factor was very high (4.70066e+13) and so Esha opened Scalar Bar tab and ound out that each Scalar Mode had very low value except DRX as shown in adjacent figure. Tis was another orque Mode. Enable Iso view to see deflection as shown in adjacent figure.

— 184 —


#

Description

11


Figure


Right Click “2601.12” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable all three view to see deflection but the mode shape cannot be seen. 12

Open the Deormed Shape window again and have a look at Scalar Bar ab. Open Scalar Mode and only DX has Max value o 1 this means that this is ension Mode as seen in the 3D mode shape as well. Sweep this mode to see how the deormation occurs.

John asked Esha to summarise her results in a table. Esha made a table which compared the natural requencies calculated by Hand and that which was calculated by Code_Aster in a table.

— 185 —


Natural requency


F1

33.5656

F2


33.5169 167.828

166.319

F3

209.785

209.648

F4

588.3517

585.235

orsion Axis F5 F6

-NA1048.9252 1153.8178

orsion Axis F7 Linear Expansion F8

590.02 996.827 1360.74

-NA-

1770.64 1876.88

-NA2941.7585

2601.12

1907.1368

F9

5769.0888

F10

9535.6839

Esha noticed that the results obtained rom 1D analysis were closer to the Hand Calculation than those obtained by 3D analysis.


How to use modiy an existing command file to make it suitable or 1D Mode shape FE analysis.

▶


— 186 —


Chapter 8 - Case 19 FE Analysis o 2D Plate or Mode Shapes Next in line was finding Mode Shapes o a 2D plate and comparing it with previously carried out 1D and 3D analysis.

— 187 —


Step 1: Purpose o the FE Analysis / Description o the problem Te main purpose or this analysis was to see i using 2D analysis or mode shapes improves the accuracy o the results over that obtained by 1D and 3D analysis. For this study we will use 2 Dimensional model and perorm a Modal FE analysis by editing the command file.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Plate are as ollows Width o the Plate: 50mm Tickness o the Plate: 10mm Height o the Plate: 500mm Material Properties o the Plate are as ollows Young’s Modulus: 2.1e5 MPa Poisson’s Ratio: 0.3 Density o Material: 7800 kg/m3 Summary o the natural requencies o the beam: 33.5656, 167.828, 209.785, 588.3517, 1048.9252, 1153.8178, 1907.1368, 2941.7585, 5769.0888 and 9535.6839 Hz.

— 188 —


Step 3: Model Geometry John asked Esha to generate the Geometry. #

Description

Figure

Click New Entity -> Basic -> 2D Sketch and enter the values as shown below. 0, 0, Click “Apply” 1

500, 0, Click “Apply” 500, 50, Click “Apply” 0, 50, Click “Apply” Click on “Sketch Closure”.

— 189 —


#

Description

Figure

Next we will create a Face with the Sketch we created earlier.

2

Click New Entity -> Build -> Face and select the “Sketch_1” we created earlier. Make sure “ry to create a planar ace” is checked. Click on “Apply and Close”.

Right Click “Face_1” and select “Create Group” In the window, select Second Shape ype and select the edge that is on the Y axis. Give it a Name “Fix” 3

Click “Apply” Create a Face group or “Guide” to give plate properties in command file. Select the whole ace and add it. Click “Apply and Close”


— 190 —


Step 4: Meshing Geometry Esha changed Geometry Module to Mesh Module and began creating mesh o the beam. #

Description

Figure


1

In the dialogue box that pops up only 2D and 1D tab is enabled to enter values, Click “Assign a set o hypotheses” and Select “2D: Automatic Quadrangulation”. In the Hypotheses Construction window enter “50” or Number o Segments and Click “OK”.

2

Mesh window adjacent figure.

looks

like

Click “Apply and Close”

Right Click Compute. 3

Mesh_1

->

I the computation is successul the mesh should look like adjacent figure.

— 191 —


#

4

Description

Figure

Right Click Mesh -> Create Group rom Geometry and in the window that pops up Select “Fix” and “Guide” rom Geometry. Click “Apply and Close”

5


— 192 —


Step 5, 6, 7, 8 and 9: Modiying comm file created by Wizard John said that we will modiy the command file generated by the Wizard in 3D Modal analysis chapter to make it suitable or 2D analysis. Copy “Case17.comm” and Paste it in the older or Case 19 as “Case19.comm” and ollow the instructions shown below. #

Description

1

First we need to change the Modelisation o the analysis rom “3D” to “DK” as shown in adjacent figure.

Figure

Next we need to speciy the dimensions o the Plate or the 2D analysis. 2

Enter the Plate definition or thickness 10 as shown in adjacent figure. Give it a name “Guide”.

— 193 —


#

Description

3

As 2D Plate has 6 degrees o reedom compared to 3 degrees o reedom or nodes o a 3D geometry, we need to restrict rotations in 3 directions.

Figure

Add DRX=0, DRY=0 and DRZ=0 as shown in adjacent figure.

Next we need to add the Element definition to the calculation. 4 Add “CARA_ELEM=Guide,” to ASSEMBLAGE as shown in adjacent figure.

5

Tis completes steps to modiy command file. Next we will create Aster study.

— 194 —


#

Description

Figure


6

Enter “2DModeShapes” as Name, Select “Case19.comm” or the command file and select “Mesh_1” rom the Object Browser. Keep everything else as shown in adjacent figure. Click “OK”

Tis completes the steps to create Aster study.

Step 10: Run the analysis Right Click on “2DModeShapes” in Aster branch and Select “Run”. Afer the analysis completed, “Post-Pro” module was NO added to the Object Browser. John said that this is the time to check the message file (.mess) and see what errors are there in the analysis. wo-third way down the message file John showed Esha that Code_Aster had calculated the Natural requencies ------------------------------------------------------------------------

CALCUL MODAL:

METHODE D’ITERATION SIMULTANEE METHODE DE SORENSEN

NUMERO

FREQUENCE (HZ)

NORME D’ERREUR

1

3.37547E+01

2.46955E-05

2

1.67876E+02

4.67677E-07

3

2.11489E+02

9.78431E-07

4

5.92653E+02

5.73354E-07

5

6.59663E+02

2.27327E-07

6

1.00763E+03

3.21664E-07

— 195 —


7

1.16321E+03

5.40778E-07

8

1.92688E+03

5.43218E-07

9

1.98912E+03

3.01588E-07

10

2.59792E+03

1.77592E-07

NORME D’ERREUR MOYENNE:

0.28827E-05

------------------------------------------------------------------------

Esha had a question on her mind and asked John that i Code_Aster did calculate the Natural requency, what was the error? John said that or that we have to keep on looking. John showed the error to Esha that Code_Aster was pointing out. -------------------------------------------------------

Erreur de vérication des modes calculés : au moins un des critères de validation renseignés sous le mot-clé facteur VERI_MODE n’est pas respecté. Conseils : Si vous voulez tout de même utiliser les modes calculés (à vos risques et périls), relancez le calcul en modiant les mots-clés situés sous le mot-clé facteur VERI_MODE, - soit en utilisant des valeurs moins contraignantes sur les critères de qualité, !

- soit en utilisant l’option STOP_ERREUR=’NON’. --------------------------------------------------------

Which when translated it means: --------------------------------------------------------

! Verication error of the calculated modes: at least one validation criteria informed as keyword factor VERI_MODE is not respected. Tips: If you still want to use the modes calculated (at your own risk), Restart the calculation by changing the keywords located under the key word factor VERI_MODE, - Or using less stringent values on quality criteria - Either by using the STOP_ERREUR option = ‘NO’. --------------------------------------------------------

John explained to Esha that afer the Modes are calculated, Code_Aster perorms a verification check o the modes. Sometimes this verification ails and this error is generated. Code_Aster has also provided a solution or the error.

— 196 —


John opened command file and added ollowing single line to MODES

Ten he saved the command file, went to Salome-Meca, Opened Aster branch and Right Clicked on “2DModeShapes” and selected Run. Tis time Post-Pro module was added to the study.

— 197 —


Step 11: Post Processing o the Results John let Esha have a look at the results. Esha enabled “Post-Pro” module. #

Description

Figure

1


2

Esha compared the results with that obtained with hand calculation. Esha decided to check the Deflected shapes o the Modes o Vibration and compare it with hand calculation.

3

Right Click “33.7547” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable iso view to see deflection as shown in adjacent figure.

— 198 —


#

Description

4


Figure

Enable top view to see deflection as shown in adjacent figure.

5


6


— 199 —


#

Description

7


Figure

Enable iso view to see deflection as shown in adjacent figure.

8

Right Click “1007.63” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. Enable top view to see deflection as shown in adjacent figure.

9


— 200 —


#

Description

10


Figure

Enable iso view to see deflection as shown in adjacent figure.

11


Right Click “2597.92” -> Deormed Shape. Enter “25” as Scale Factor and ick Magnitude Colouring. 12

Enable iso view to see deflection as shown in adjacent figure. Esha realised that this is the tension Mode shape that we saw in previous two analysis.

John asked Esha to summarise her results in a table. Esha made a table which compared the natural requencies calculated by Hand and that which was calculated by Code_Aster in a table.

— 201 —


Natural requency


F1

33.5656

F2


33.7547 167.828

167.876

F3

209.785

211.489

F4

588.3517

592.653

orsion Axis F5

-NA1048.9252

659.663 1007.63

F6

1153.8178

1163.21

F7

1907.1368

1926.88

orsion Axis Linear Expansion F8

-NA-NA2941.7585

F9

5769.0888

F10

9535.6839

1989.12 2597.92

Esha noticed that the results obtained rom 2D analysis were closer to the Hand Calculation than those obtained by 3D analysis.


How to use modiy an existing command file to make it suitable or 2D Mode shape FE analysis.

▶


▶

How to check message (.mess) file to check or errors.

▶

What needs to be done to rectiy error and how to use Code_Aster or solution.

— 202 —

Thermal Conduction FE Analysis

Chapter 9 - Case 20 Termal Conduction FE Analysis Next Esha wanted to learn how to conduct thermal analysis with Salome-Meca and Code_Aster. John asked Esha i she knew that Salome-Meca has a wizard that can do Termal FE analysis. Esha said that she has already tried the Salome-Meca wizard but the only thing that it outputs is temperature distribution. John asked Esha to conduct a FE analysis o a wall 1m wide by 1m tall that has one ace on ice at the other ace there is steam. Te thickness o this wall is 0.01m. He wants her to plot the temperature profile. Esha asked i then John can then show her how to plot Heat Flux on the same analysis.

— 203 —


Step 1: Purpose o the FE Analysis / Description o the problem Te problem analysed in this case is a basic case o thermal conduction taught as a undamental analysis. Te geometry and material properties or this study are noted below. For this study we will use 3 Dimensional model and perorm a Termal Conduction FE analysis.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Wall are as ollows Width o the Wall: 1m Height o the Wall: 1m Tickness o the wall: 0.01m Material Properties o the Wall are as ollows Termal Conductivity: 54 W/m.K John asked Esha to do a manual calculation or the Heat Conduction o a Wall so that the results can be verified.

— 204 —



Description

Figure

For generating Wall model, Esha started with the use o Primitive shape. 1

Click New Entity -> Primitives -> Box and enter the values as shown in the figure and change its Name to “Wall”. Click on “Apply and Close”.

Create Face groups or “Ice” boundary condition which is the ace at the origin having temperature o 0°C. 2 Ten create a ace group or “Steam” which is the opposite ace to the origin having temperature o 100°C.


— 205 —


Step 4: Meshing Geometry Esha #

changed

Geometry

Module

Description

to

Mesh

Module

Figure


1

In the dialogue box that pops up, Click “Assign a set o hypotheses” and Select “3D: Automatic Hexahedralization”. In the window or Hypotheses Construction enter “10” or Number o Segments and Click “OK”.

2

Te Mesh window should look like adjacent figure afer you change the Name to “Wall”. Click “Apply and Close”.

— 206 —

and

began

creating

mesh

o

Wall.


#

Description

Figure

Right Click Wall -> Compute. 3

Final Mesh should look like adjacent figure.

— 207 —


#

5

Description

Figure

Right Click Wall -> Create Group rom Geometry and in the window that pops up Select “Ice” and “Steam” rom Geometry. Click “Apply and Close”

6


— 208 —


Step 5, 6, 7, 8 and 9: Creating command file by Wizard Esha knew that next step is to use Aster wizard to generate the study or Termal Analysis. She started Aster Module. Click Aster -> Wizards -> Linear thermic Analysis #

Description

1

In the first ab keep deault “3D” selected.

Figure

Click “Next”.

2

In Linear thermal Analysis ab, Select “Wall” or Mesh and make sure that “Use geometrical groups” is selected. Click “Next”.

— 209 —


#

Description

Figure

In Material Properties, Enter the inormation as shown in the adjacent figure. 3

Remember that deault units are m or Length, so the unit or Termal conductivity is W/(m x K). Click “Next”.

For Boundary Condition, Select “Ice” and enter “0” or emperature. 4

Add another line by clicking on the “+” and Select “Steam” and enter “100” or emperature. Click “Next”.

— 210 —


#

Description

Figure

5

Leave blank or the Streams normal to a ace. Click “Next”.

6

Leave blank sources.

or

volumic

Click “Next”.

— 211 —


#

Description

7

Save the file in the location where you saved the study as “Case20.comm”.

Figure


Step 10: Run the analysis Right Click on “linear-thermic” in Aster branch and Select “Run”. I the analysis runs successully a Post-Pro branch will be added to the Object Browser.

— 212 —



Description

1


2

Esha Right Clicked on “0” -> Scalar Map and selected deault in the window. She got displayed.

3

Figure

ollowing

results

Esha said that even though she was able to see the temperature profile, she was not able to see the Heat Flux. John said that this was something that can be fixed easily.

— 213 —


#

Description

Figure

John opened “Case20.comm” and added ollowing lines beore Code_Aster is about to save the result to med file.

4

— 214 —


#

Description

Figure

Esha re-run the analysis and had a look at the results. 5

Te Object Browser showed three more results as shown in adjacent figure.

Open EMP___FLUX_NOEU -> Right Click “0” -> Scalar Map. Keep Everything deault. 6

Te results or Heat Flux is shown below. It can be seen that the Heat Flux is constant throughout the Wall, which is sel evident.

7

Esha compared this result with hand calculation and ound that the results match perectly.

— 215 —



How to use Aster Wizard to conduct Termal Conduction FE Analysis

▶

How to edit the command file to add Heat Flux to the results.

▶

How to compare the results with hand calculation.

— 216 —

Thermal Convection FE Analysis

Chapter 10 - Case 21 Termal Convection FE Analysis Esha was excited to learn new type o FE analysis in Code_Aster. She asked John whether Code_Aster was able to carry out a bit more high level Termal analysis than what he showed her in previous example. John asked Esha to give a real lie scenario which they can model. Esha told John that some time ago she saw a Termal analysis perormed by another Engineer in her company. Tis analysis was about Termal Convection. Tey wanted to find out the temperature o the Pipe Shoe base when the temperature in the pipe was 150°C and the air temperature was 25°C.

— 217 —


Step 1: Purpose o the FE Analysis / Description o the problem Te problem analysed in this case is a basic case o thermal convection where heat will flow rom inside o the pipe to the pipe shoe. Te geometry and material properties or this study are noted below. For this study we will use 3 Dimensional model and perorm a pseudo Termal Convection FE analysis.

Step 2: Input values or the FE analysis Input values or the Analysis are shown below. Dimensions o the Pipe and Shoe are as ollows OD o pipe: 300mm ID o pipe: 280mm Pipe Shoe height: 100mm Pipe Shoe Tickness: 10mm Length o Pipe Shoe: 300mm Pipe shoe is o the shape o Inverted . Material Properties o the Wall are as ollows Termal Conductivity: 54 W/m.K Convection Coefficient o air:

— 218 —



Description

Figure

For generating Pipe Shoe model, Esha started with the use o Primitive shape.

1

Click New Entity -> Primitives -> Cylinder and enter the values as shown in the figure or Cylinder_1. Click “Apply”. Enter 140 or Radius and 600 or Height or Cylinder_2 and Click on “Apply and Close”.

— 219 —


#

Description

Figure

For the actual Shoe we will create a 2D sketch. Enter the ollowing values and Click Apply every time. X, Y

0, 0 5, 0 2

5, -250 50, -250 50, -260 -50, -260 -50, -250 -5, -250 -5, 0 Click Sketch Closure.

— 220 —


#

Description

3

Next we will translate this Sketch to its proper location as shown in adjacent figure.

4

Ten we will create a Planar ace rom the Sketch as shown in adjacent figure.

Figure

— 221 —


#

Description

5

Ten we will extrude this ace in OZ direction by 300mm as shown in adjacent figure.

6

Next we will use “Cylinder_1” and “Extrusion_1” as shown in adjacent figure.

Figure

— 222 —


#

Description

7

And then we will Cut “Cylinder_2” rom “Fuse_1” as shown in Adjacent figure.

Figure

Give it a Name “PipeShoe”.

8

Create a Face Group o the Inside Diameter o the Pipe and give it a Name “Hot” as shown in adjacent figure.

— 223 —


#

Description

9

Next create Face Group “Cold” o all suraces except the Inside Diameter o the Pipe and the two End aces o the pipe.

Figure


— 224 —


Step 4: Meshing Geometry Esha changed Geometry Module to Mesh Module and began creating mesh o Pipe shoe. #

Description

Figure


1

In the dialogue box that pops up, in 3D tab, Click “Netgen 1D-2D-3D” or Algorithm and Click on the Gear button next to Hypothesis and Select “Netget 3D Parameters”. In the window or Hypotheses Construction enter “10” or Max Size and “5” or Min Size. Select “Fine” or Fineness and leave everything else deault. Click “OK”.

— 225 —


#

Description

Figure

2

Te Mesh window should look like adjacent figure afer you change the Name to “PipeShoe”. Click “Apply and Close”.


PipeShoe

->


— 226 —


#

4

Description

Figure

Right Click PipeShoe -> Create Group rom Geometry and in the window that pops up Select “Hot” and “Cold” rom Geometry. Click “Apply and Close”

5


— 227 —


Step 5, 6, 7, 8 and 9: Creating command file by Wizard Esha asked John to explain her what should a command file have or Termal Convection. John said that we will use the command file rom previous Case and modiy it to suite. Copy “Case20.comm” to Case21 older and rename it “Case21.comm” #

Description

1

First we need to change the value o Lambda rom “54” to “0.054” as shown in adjacent figure.

Figure

Tis is required as the unit system we are ollowing is mm instead o m

Next we need only 1 temperature definition, or Hot surace. 2

Change “LOADING” as shown in adjacent figure.

— 228 —


#

Description

Next or Convective transer we need parameters.

Figure

heat two

First is Convective Heat ranser coefficient, which or Natural Convection o air is considered to be in the range o 3

(5 to 25) x e-6 W / sq mm x K. We will assume 25 e-6. Second is Outside air temperature which was defined as 25°C. Tese two values will be added with ECHANGE as shown in adjacent figure. Rest everything remains same.

4 Tis completes steps to modiy command file. Next we will create Aster study.


5

Enter “TerConvection” as Name, Select “Case21.comm” or the command file and select “PipeShoe” mesh rom the Object Browser. Keep everything else as shown in adjacent figure. Click “OK”


— 229 —


Step 10: Run the analysis Right Click on “TerConvection” in Aster branch and Select “Run”. I the analysis runs successully a Post-Pro branch will be added to the Object Browser.


Description

1


2

Figure

Esha opened “EMP__EMP” branch -> Right Clicked on “0” -> Scalar Map and selected deault in the window. She got ollowing results displayed.

— 230 —


#

Description

Figure

— 231 —


#

Description

Figure

3

Esha saw that i the pipe is not insulated and i there is natural convection the bottom plate o the pipe shoe reaches temperature o 65°C.

John told Esha that this figures are based on ormulas and the value o Coefficient o Termal convection. I true results are required, it is required to conduct a real thermal analysis with fluid dynamics or thermal analysis coupled to it.


How to modiy a command file to conduct Termal Convection FE Analysis

▶

What parameters are required or Termal Convection FE Analysis.

— 232 —

What will be covered in Volume 3

What will be covered in Volume 3 Learning new topics rom John, Esha was equipped with new enthusiasm. She started working again and the projects that ormerly she had to orward to her colleagues due to lack o understanding, she could do them with ease. Nearly afer a year, John caught up with Esha to find out how she was eeling regarding the use o new and a bit more advanced use o Open Source Sofware or Finite Element Analysis. Esha, now a seasoned engineer, told John that she was very happy to get new inormation or the help that he had provided her as it helped her in her job. She could do the projects with ease and now was also able to teach others the use o Open Source Sofware. Ten Esha told John that every now and then an advanced type o FE Analysis comes to her or which she is not ready yet. She has to pass them to her other colleagues as she is not eeling confident and she is eeling a bit lost. As usual John was listening to her words careully and asked her i he could help. Esha was waiting or John to say that and she listed the analysis which she elt were a bit tough or her to do.

Using Python or Parametric Modelling and FE Analysis Esha said that using Python or Parametric modelling was good, but every now and then when she has to re-run the study, with more refined mesh, she had to re-do all the steps again. She wanted to know i using Python, can she automate the phase o Modelling, Meshing and running the analysis.

Using Hommard or adaptive meshing Esha had heard about Hommard and that it can be used or adaptive meshing. She wanted to learn how to use it.

Advanced Termal FE Analysis Afer learning about two types o Termal FE Analysis, conduction and convection, Esha wanted more. She asked John i he could teach her advanced Termal Analysis. She wanted to learn Termal Radiation, Termal Analysis o an Assembly and so on.

Termo-Mechanical FE Analysis Finding out the temperature o different parts in Termal analysis is good, but there was something missing. Esha wanted to learn, how to find out thermal deormation in a part or assembly. She wanted to know i the thermal Stress Strain curve o the material can be attached to thermal and mechanical analysis.

Pipe Stress Analysis Esha knew that standard Pipe Stress Analysis programs available in the market use Beam model or Stress analysis. She wanted to learn how to perorm Pipe Stress Analysis using Salome-Meca and Code_Aster.

— 233 —


Fluid Structure Integration Esha remembered that doing Computational Fluid Dynamics, you can find out the pressure on the boundary walls, she wanted to know i there was a way to project these on to the mechanical parts and carry out FE analysis. In short she wanted to learn Fluid Structure Integration o FE Analysis. Afer listing the above analysis, Esha looked at John who was smiling and had a sparkle in his eyes. John was ready to teach Advanced FE Analysis to Esha. John told Esha that both Salome and Code_Aster were capable o conducting the analysis she asked or and much more.

— 234 —

Appendix A

Appendix A Other sources o inormation Tis section is provided here or motivated users who are hungry or more inormation on the sofware covered in this book. Links are provided to the Sofware home page and also to the User Forums. Links provided to the websites are correct at the time o writing this; i by any chance these links don’t work, just use any search engine to find relevant sofware. 1. Salome website http://www.salome-platorm.org/ 2. Code Aster website http://www.code-aster.org/V2/spip.php?rubrique2 3. CAELinux website http://www.caelinux.com/CMS/ 4. Efficient website http://engineering.moonish.biz/efficient/ 5. Salome orum http://www.salome-platorm.org/orum 6. Code_Aster orum http://www.code-aster.org/orum2/ 7. CAELinux wiki http://www.caelinux.org/wiki/index.php/Main_Page

— 235 —


Appendix B Installing Sofware required or this book All case studies mentioned in this book can be perormed on a computer that has Ubuntu 12.04 Operating System and which has Salome-Meca and Efficient installed on it.

Ubuntu 12.04 Configuration Ubuntu 12.04 can be installed on a computer alongside Windows 7 or it can be installed as a Virtual Operating System. Decision o how to install Ubuntu is lef to the readers. I have installed Ubuntu 12.04 in a virtual environment using Virtual Box. Configuration o Ubuntu on Virtual Box is shown below

— 236 —

Appendix B

Salome-Meca 2013.2 installation Download Salome-Meca 2013.2 rom their website http://www.code-aster.org/V2/spip.php?article303 It downloads as a rar file and it is in my Downloads older as shown below.

— 237 —


Now Open erminal and go to Downloads Folder

Enter the command by typing in erminal

— 238 —

Appendix B

tar xvf SALOME-MECA-2013.2-LGPL.tgz &&./SALOME-MECA-2013.2-LGPL.run

Follow the prompt and install Salome-Meca 2013.2 in desired location. Once Salome-Meca installation is complete, a desktop icon will be created which can be double clicked to start Salome-Meca 2013.2 Have un. I you have any trouble installing the sofware, consult Code_Aster Forums on http://www.code-aster.org/orum2/vieworum.php?id=26

Efficient Install Efficient is developed in Java and to run it in Ubuntu, you will need OpenJDK Java 7 runtime. o download and install it go to https://apps.ubuntu.com/cat/applications/precise/openjdk-7-jre/

Install it on your Ubuntu installation.

— 239 —


Download Efficient version 0.1.1 rom http://engineering.moonish.biz/efficient/

On the right hand side latest Efficient version can be downloaded. Click on “Download v0.1.1” and a Java Jar file named “Efficient_v0-1-1.jar” will be downloaded on your computer. Copy it to a proper location. o run Efficient, Right Click on “Efficient_v0-1-1.jar” and Select “Open With OpenJDK Java 7 Runtime”

— 240 —

Appendix B

— 241 —

Intermediate-Finite-Element-Analysis-with-Open-Source-Software.pdf

Recommend Documents