NOORUL ISLAM COLLEGE OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING PRE-FINAL YEAR COMPUTER AIDED DESIGN (ME335) TWO MARK QUESTION QUESTI ON AND ANSWERS
1.THE DESIGN PROCESS 1. Define geometric modeling ? The The geom geomet etri ricc mode modeli ling ng conc concer erne ned d with with comp comput uter er comp compat atib ible le mathematical description of geometry of an object. The mathematical description should be such that the image of the object can be displayed and manipulated in computer terminal, modification on the geometry can be done easily and the image can be stored in computer memory retrieve back to display in computer screen for review, analysis or alternation. 2. Name phases related to production-consumption production-consumption cycle in morphology of design. design. (a !lanning !lanning for for production production (b !lanning !lanning for distri distributio bution n (c !lanning !lanning for for consumption consumption (d !lanning !lanning for retirement retirement ". What is ADAMS ? #$#%& is an acronym of #utomatic $ynamic #nalysis of %echanical &ystem. 't is one of kinematics analysis software. .
Mention two important design analysis carried out using 3D model. (a #nalysis #nalysis for for mass mass properties properties (b )inite )inite *lement #nalys #nalysis is ()*#
+. Define +. Define CAPP #$ database used for process planning activites (i.e. two determine the order of machining other manufacturing processes are known as computer aided process planning (#!!. !.
What is meant "y C#PMS %any of the activities of production planning and control (!! can be carried with help of computers are known -omputer 'ntegrated !roduction %anagement &ystems ('!%&.
$. What are elements of CA% 1. omputer #ided $rafting. 2. omputer #ided $esign ". omputer #ided %achining /. Mention one application of CA%. (a 'n the design and development of plastic injection models, #* helps in (i $esign of mould base configurations which are b ased on constraints relating to resin temperatures and pressure. (ii %oulding re0uirements and (iii the type of mould and %oulding machine to be used etc. . Define CAD. Mention areas of application of CAD. The computers help in design and draft is commonly epressed by the term -omputer #ided $esign (#$. # #$ system helps designer in various ways 1. 'nvites and promotes interaction through various input3output devices. 2. #llows manipulation of image (such as scalling, translation, rotation in the computer screen. ". *nable the designer to carry out the engineering analyses for stress, vibration, noise thermal distortions and more using )*#. . $esign optimi4ation through simulation and animation. +. #utomated drafting.
&'. Define CAM The computer help in any non design function (such as process planning, production planning5control, machining, 0uality control, assembling and packaging 6f manufacturing known as -omputer #ided %anufacturing (#%. &&. Define and classify CA(C The computers used in 0uality control activities are known as computer aided 0uality control (#7.This can be classified into omputer #ided 'nspection (#' and omputer #ided Testing (#T &). What is meant "y Modular construction and e*plain its use 't means that the main assembly of the product should be divided into no of modular3sub assemblies. This makes the assembly process easier, since sub assembly works are carried out separately and hence time for assembly reduces. &3. What is meant "y sandwich construction and e*plain its use 8oth in main assembly and sub assemblies of the product, components are to be assembled one by one. The positioning of a component is made easy by previously assembled parts. #dvantages is that a pick and place robots can be used in assembly works.
&+. What is meant "y concurrent engineering
The concept and practice of various functions or departments working together, from the beginning, to engineer a product. &,. What is DM $)% ($esign for manufacturability or manufacturing or manufacture.'t is the set of rules to be followed at the product design stage itself, to facilitate production. &!. Define CA% #* (omputer #ided *ngineering.The use of computer system for functions that are essential to engineering a produ ct. &$. Name any + reasons for implementing CAD in design 1. #$ can make each design step much easier and less tedious for designer to perform. 2. *rrors during change of design will be less. ". %odels generated can be easily manipulated and modification in the model can be done very easily carried out in the system itself.
&. What are main features of drafting software 1. $rawing utilities9units, limits, scalling, grid, snap etc.layer, line type, tet si4e, and, font etc. 2. $rawing entities9line, arc, circle, polygen, bo, sphere, cone etc. ". *diting9 erace, undo, move, etent, offset etc. . 8lock option +. $imencing option. :. !lotting. &/. What is an operating system #n operating system (;& is a set of interrelated collection of supervisory software that control the over all operation of a computer to supervise it
)). What are the ad0antages of Concurrent engineering
1. The design decisions are taken by a team of multi disciplinary eperts. 2. hanges and modification on the product design will be faster. ". =igher 0uality. )3. What are the "enefits of CAD 1. >ew products are desigbed faster. #$ can drastically reduce the number of steps involved in the design process for a particular product and can also make each design step much easier and less tedious for designer to perform. 2. =ard copy of the drawings are of better 0uality. hence there will be less ambiguity and better 0uality. ". *rrors during change of design will be less. )+. What are the characteristics of concurrent engineering 1. !roduct responsibilities lies on team of multi disciplinary group. 2. 'ntegration of design, process planning and production will be achieved. ". )re0uent review of design and development process. . apid prototyping.
2.INTERACTIVE COMPUTER GRAPHICS
&1 Define computer graphics. omputer graphics may be defined as the process of creation, stortage and manipulation of drawings and pictures with the aid of a number. )1 What are the functions of #2C a. &olid modeling b. &torage c. %anipulation d. @iewing 31 What are the 0arious display control facilities in graphics i. @ector Aeneration ii. Bindowing and viewing transformation. iii. lipping transformation iv. Cooming v. !anning vi. Transmitting information on a network and vii. Araphics libraries.
+1 What is meant "y 0iew point
The viewpoint is the area on the screen in which the contents of the window are to be displayed as an image. ,1 What is 0iewing transformation and windowing transformation The processs of mapping from the model co9ordinate system to the screen co9 ordinate system is known as viewing transformation The viewing transformation in which no rotation is applied is called the windowing transformation. !1 What is meant "y Clipping lipping is the process of determining the visible portion of a drawing lying within a window and discarding the rest. D State the use of reflection transformation. 't allows a copy of the object to be displayed while the object is reflected about a line or a plane. 1 What is the use shading echni4ue This techni0ue is used to display the images in natural way. 't is based on the recognition of distance and shape as a function of illumination. /1 5ow information is transmitted on a networ6 The data must be encoded using a protocol. !rotocol is a set of rules that control the echange of data between the communicating devices. &'1 What are the main types of )D transformations i. Translation ii. &caling iii. eflection iv. otation v. &hearing &&1 State the hidden line elimination. The hidden line elimination can be stated as, -)or a given three dimensional scene, a given viewing point and a given direction, eliminate from an appropriate two dimensional projection of the edges and faces which the observer can not see. &)1 2i0e any two characteristics of 7e8ier cur0es. a. The curve is tangent to the first and last segments of the characteristics polygon. b. The curve is symmetric with respect to u and (19u. Therefore, the se0uence of control points defining the curve can be reversed without change of curve shape. &31 Distinguish "etween 7e8ier cur0es and Cu"ic Spline cur0e.
S.N!. 1.
2.
"#$%#& '&#* The shape of 8e4ier curve is controlled by its defining points only The curve does not pass through the given data points. 'nstead, these points are used to control the shape of the resulting curves.
C+%' S,%# '&# )irst order derivatives are used in the curve development.
These curves pass through the given data points only.
&+1 What are the characteristics of 7-spline cur0es a. The 89spline curves do not pass through the first and last control points ecept when a linear blending functions are used b. # non9periodic 89spline curve pass through the first and last control points and is tangent to first and last segments of control polygon. c. # second degree curve (kE" is always tangents to the midpoints of all the internal polygon segments
1+ Define rational cur0e. ational curve is defined by the algebraic ratio of two polynomials while a non9rational curve is defined by one polynomial. &!1 Define data"ase. $atabase can be defined as a collection of data in a single location designed to be used by different programmers for a variety of applications. &$1 Mention the ways of using data structure in interacti0e modeling. a. 't allows interactive manipulation such as addition, modification and deletion of data. b. 't supports multiple types of data element like geometric, tetual, dimensions, labels. Tool paths, finite, elements and so on. c. 't allows the property such as pen number, line style, color and so on to be associated with geometric elements. &1 2i0e the ad0antages of centrali8ed data structure. a. *nforce standards that mean with central control of the database, both the national and international standards are followed. b. #ccess to sensitive data and projects can be checked and controlled by assigning each used proper access code to various parts of the database. c. 8alance conflicting re0uirements. &/1 State the 0arious acti0ities of data "ase management.
;rgani4e a database #dd a new data to the database &ort the data in some meaningful order search the database for types of information !rint the data into formatted reports *dit the data and delete the data
)'1 What re the elements of information system 1. !lanning and control 2. ;peration element and ". *valuation element )&1 What are the pro"lems surrounding data"ase. a. There is possibility of invalid input information by a unit wishing to maintain information security. b. 'f anybody enters the Ferror< data, it affects other departments immediately and produces -multiplier effect. ))1 What re the aspects of data life cycles 1. Be need how data are generated i.e. how they are born. 2. Be need to know what manipulation or processing of data is carried out. )31 What are the special features for a good data"ase system a. &atisfy current and future application needs. b. @alidate data before storage c. 8e easy to modify with changes d. 8e epandable with growth and changes e. #llows access for the data only to authori4ed persons. )+1 What are the characteristics needed for a good information system a. 't should undertake the various activities of ac0uisition, processing, retention, transmission and reporting of information. b. 't should be designed to follow the pattern and structure of management at all levels of the organi4ation. c. 't should not restrict the informal passage of information throughout the organi4ation.
),1 What are the two modes of data storage 1. &e0uential form and 2. andom form )!1 What are the ad0antages of data "an6
a. The accumulation of information in an information center where -;ne set of books is maintained avoids the maintenance of separate record files. b. 't tends to integrate the separate functions and departments of the company3'ndustry. )$1 What are the ad0antages of ha0ing centrali8ed control of data"ase 1. *liminate redundancy 2. %aintain integrity which ensures its accuracy. 'ntegrity proceeds consistency. ". 8alance conflicting re0uirements. )1 What a re the characteristics of relational data structure 1. *ach cell in the table holds any one field. 2. >o two rows or records can be identical. 'n an at least one of the columns there must be at least one entry that is uni0ue.
3.SOLID MODELLING 1. Classify geometric modeling . 1.wire frame modeling. 2. &urface modeling. ".solid modeling. )
Define sculptured surface. &culpture surface means the surface produced by combining two families of curves that intersect one another in crisscross manner. reating network of inter connected patches. ". What is meant "y lofted surface This is linear surface. 't interpolates linearly between two9boundary curves. +
9ist the common entities of a typical surface modeler 1. !lane surface. 2. uled (lofted surface. ". &urface of revolution. . Tabulated surface. +. 8e4ier surface. :. 89 spline surface. D. ones patch. /. )illet surface. . ;ffset surface.
+. Name the two "asic approaches followed in solid modeling. a. onstructive solid geometry (&A or (9rep. b. 8oundary representation (8 9 rep. :. 9ist the "asic entities a0aila"le in CS2 approach of solid modeling . (1 ubold (2 ylinder (" &phere ( one (+ Bedge (: Torus.
/. State %uler rule for topological chec6ing. @9*G)E2 Bhere, @ E number of vertices. * E number of edges. ) E number of faces. . State %uler-Poincare formula for topological chec6ing. @ 9 * G ) 9 = G 2) E 28 Bhere, @ E number of vertices. * E number of edges. ) E number of faces. = E number of holes. ) E number of passes or through holes. 8 E number of separate bodies. 16. 9ist some of the solid modeling softwares !ro3*, '$*#&. Hnigraphics, #T'#, &olid works, &olid *dge, #uto#$ etc. 11. Define parametric modeling. #n approach to model parts belong to a family, rather than modeling the eact parts, a generic part is modeled with its dimensions as variable. The designer or application program simply specifies the variables value parameters to develop a specific part model from the generic model. 12. What are the types of parametric modeling (1. Aeometrically parameteri4ed modelI 9 in which dimensions of the shape only be changed, but not the structure of the model. (2. Topologically (or structural parameteri4ed modelI 9 in which both shape and topological arrangement of the model along with dimensional change will be incorporated in the model. 1". What is meant "y feature )eature has two meaning (a Aeometrical meaningI 9 shapes such as drilled holes, ribs, bosses in casting, grooves on the shaft etc are considered as feature. (b*ngineering meaningI 9 machining operations or attributes of components or data of components like material properties etc. 'n general, feature means prototypical shape with some engineering or memory.
1. What is meant "y #mplicit:une0aluated feature 'n this, the full detail of the feature will not be given only essential details will be given. ;ther data is calculated from essential details. *ampleI for gears only module and number of teeth will be given as essential data. 1+. 9ist the types of interfacing in CADCAM en0ironment a. =ardware 9 hardware interfacing. b. =ardware 9 software interfacing. c. &oftware 9 software interfacing. 1:. 9ist some of neutral file format to achie0e software interfacing ';*& 9 initial graphics echange format. $J) 9 data echange format. &T*!9 standard for echange of product data !$*& 9 product data echange. 1D. What are the types of design analysis that can "e carried our using 3D models a. %ass property analysis. b. )inite element analysis. 1/.What is PD%S !$*&(product data echange specification. # specification for breading 'A*& to incorporates both design and manufacturing data. !$*& bridges the gap between #$ and #% by encouraging data echange among different #$'#% system.
.FINITE ELEMENT ANALYSIS
1 Classify the "oundary conditions. 1. !rimary boundary condition (or *ssential 8.. (or geometric 8.. 2. &econdary boundary conditions (or natural 8.. )1 What are the three phases of %M (a 8andwidth solver (b &kyline solver (c )rontal solver 31 What are the three phases of %M (a !re processing (b #nalysis (c !ost processing
+1 White are the different forms in which the %M solutions are represented in post processing (1 a"ulation orm; =ere, the re0uired numerical results are printed in a table at all nodes and3or at all elements at selected nodes or elements or at selected points inside element. (2 2raphical orm; To aid the visuali4ation of results, the results are also represented in graphical form, like stress contours, animation of displacement etc. ,1 What is meant "y discreti8ation in %M $ivide the domain into nodes and elements is known as discreti4ation. !1 What do you mean "y D.<.. of a node 'n )*%, number of primary variables to be determined per node is known as -$egree ;f )reedom of a node. $1 Name the different 0ariational methods. 1. it4 method 2. ayleigh9it4 method 1 During discreti8ation= mention the place where it is necessary to place a node (1 !oints at which the concentrated load acts. (2 !oints at which abrupt change in load occurs. (" !oints at which the cross section change occurs ( !oints at which different materials interjunction occurs. /1 Where are >h?? and >p? 0ersions in .%. method The accuracy of the )*% solution can be improved by several ways. '> conventional approach called h9version of finite element method, the order of polynomial approimation for all elements is kept constant and the number of elements are increased in such a way that the si4e of the largest element (hma approaches to 4ero. 8ut in p9versions the number of elements is maintained constant and the order of polynomial approimation of element is increased. &'1 What is the difference "etween static and dynamic analysis Static analysisI The solution of the problem that does not vary with time is known as static analysis. *ampleI &tress analysis on a beam, hoop stress distribution on the cylindrical wall subjected to internal pressure, etc. The static analysis can be further divide into Kinear # non9linear static analysis. The non9linearity in the static analysis arises because of one or more combinations of the factors given below. 1. %aterial non9linearity of the material is not linear.
2. Karge strain3large deformation9here stress or strain is within elastic limit 8ut deformation is high Dynamic analysis; The solution of the problem varies with time. *ampleI 'mpact load ;n a structure, vibration problems to find natural fre0uency or Transient response. =ere also the analysis can be further divided into linear and non9linear analysis.
11 Name any four %A softwares. 1. #8#&H& 2. #$'># ". #>&L& . >#&T#> +. ;&%;& :. >'&# &)1 What is meant "y @7oundary 0alue pro"lem 'n physical problems, we seek a solution of differential e0uation which satisfies some specified conditions known as the boundary conditions. The differential e0uation together with these boundary conditions, constitute a boundary value problems. There are two types of boundary value problems vi4. linear and non9 linear. &31 Slate the meaning and significance of shape function. 'n )*%, field variables within an element are normally epressed in terms of nodal values. )or eample, 1$ aial element HE>1H1G>2H2 The shape functions decide the field variable contribution from each node. The field variable FH< within the element depends upon the nodal value H1 and H2 and the actual magnitude depends on the shape functions >1 and >2 &+1 What are 2lo"al and natural co-ordinates Alobal co9ordinatesI 't is a co9ordinate system using which all elements are referred. >atural co9ordinateI 't is a local co9ordinate within the element which normally varies between 6 to 1 and 91 to G1. This system is normally represented by M in 1$ and by M and N in 2$ elements. &,1 What is meant "y element conducti0ity *lement conductivity is nodal information of each individual element to form the complete physical system.
&!1 What is meant "y @#nitial 0alue pro"lem The differential e0uation together with initial conditions constitutes an initial value problem. The general form of nth order initial problem is in the form of dyn (t E fOt, y(t, y1(t, y11(t,PQ dt Bith initial conditions y(to E yo, y1(to E y1o &$1 What is higher order element #ny element with a second order or a higher order interpolation function is called as higher order element. Bithin the element the field variable varies non9 linearly. &1 What is truss element The truss element is the part of a truss structure linked together by point joints that transmit only aial force to the element. &/1 7riefly e*plain node num"ering and "andwidth. The half band width or semi band width or semi band width is defined as the Areatest number of coefficient of stiffness in any row of the global stiffness %atri from and leading diagonal to the outside right9hand non94ero coefficient. The half band9width of the banded stiffness matri is given by n b E ndR(mG1 where, nd E$egrees of freedom per node mE %a difference in node numbers of an element. )'1 What is meant "y @Aspect Batio The aspect ratio is defined as the ratio of the longest dimension @s the shortest dimension of a 0uadrilateral element. 'n many cases, as the aspect ratio increases, the inaccuracy of the solution increases. )&1 Mention the D.<.. for a space frame element The space frame element will have : $.;.). per node. Therefore, total $.;.). of the element is 12. ))1 Name two ad0antages of post processing. 1. e0uired result can be obtained in tabular or graphical form. 2. ontour diagrams and animated views will help to understand the solution easily and 0uickly. )31 What is post processing in %M !ost processor is also a graphical aid, which helps in interpretation of analysis result. The post processor accepts the nodal solutions from analysis and calculates the re0uired results like stress, strain etc. 't displays the result in the form of tables, graphs, contour diagram etc. for better understanding.
)+1 What is pre processing in %M %anual preparation of input data is tedious, time consuming and error prone work, particularly while modeling "$ geometries, preprocessor is a graphical aid which helps in preparation of input data. 't gets min input the user, and creates the ).*. model and other re0uired for analysis and displays the model in the screen for checking and correction to be done on the model interactively by user. ),1 What are ad0antages of %M 1. 'rregular geometries can be modeled more accurately and easily 2. 'mplementation of any type of boundary conditions is very easy. ". #ny type of loading can be handled. )!1 What are the limitations of %M 1. )*# softwares are costlier 2. ;utput result will vary considerably, when the body is modeled with fine mesh when compared to body modeled with course mesh.
PART /" U%0 1
T# D#*% P&!'#**
1.Bhat 's $esign !rocess. *plain 8riefly The &teps 'nvolved 'n $esign !rocess 8y &hiegly ? D&.S4 S% P#! 262-265 2. *plain 8riefly The )our %odels ;f )or The $esign !rocess? D&.S4 S% P#! 263-272
". Bhat 's omputer #idede $esign ? $iscuss The @arious $esign elated Tasks !erformed 'n #$? D&.S4 S% P#! 272-275
.Brite # &hort >ote ;n &imultaneous *ngineering 5 oncurrent *ngineering? D&.S4 S% P#! 561-565
+.ompare &imultaneous *ngineering 5 The oncurrent *ngineering? D&.S4 S% P#! 561-565
:.Bhat #re The @arious &teps 'nvolved 'n The !roduct ycle? D&.S4 S% P#! 568-561
U%0 2 I0#&9'# C!:,0#& G&,%'*
1.Bhat #re The 2d 5"d ontrol )acilities. *plain 'n 8rief Bith )igures.? D&.S4 S% P#!
3;3-3;5 3;7-3<1
2. *plain The @arios 2d Transformation? D&.S4 S% P#! 3;;-3;7
".*plain The @arious "d Transformation? D&.S4 S% P#!
3;7-3<2
. Kist The @arious 'nput $evices )or Araphics 5&tate Their )unction? D&.S4 S% P#! 338-33 +.*plain 'n 8rief The lipping Transformation? D&.S4 S% P#!
3;
:. Brite &hort >otes ;n %odel &troage 5$ata &tructure? D&.S4 S% P#! 362-372
U%0 3 S!%4 M!4#%
1.Bhat 's Aeometric %odelling? *plain The Aeometric %odels, 8ringing ;ut Kimitations 5 #pplications? D&.S4 S% P#! 372-37<
2. $escribe The Techni0ue )or &urface %odelling? D&.S4 S% P#! 26-38 I+&%: =%#4 P# !2;3-2<8 ". ompare 89ep 5 9ep? D&.S4 S% P#! 85-13
. =ow "d &olid %odels an 8e reated . *plain 8riefly The %ethods? D&.S4 S% P#! 17-21
+.Bhat 's &olid %odelling? *pain 'n 8riefly The 89ep 5 9ep? D&.S4 S% P#! I+&%: =%#4 P#!
82-13 3;6-3<6 366-15
U%0 F%%0# E#:#0 A>*%*
1.*plain 8riefly The )inite *lement %ethods? Kist The 8asic &teps 'nvolved 'n This %ethods? D&.S4 S% P#! 58 I+&%: =%#4 P#!6<<-6<7
2.*plain The &teps 'nvolved 'n )inite *lement %odelling? D&.S4 S% P#! 5;2-5;5 I+&%: =%#4 P#!6<<-6<7 ". $iscuss The $irest %ethods ;f )ormulating haracteristic %atrices 5@ectors )or )*%? D&.S4 S% P#! 5;-56
. Bhat onsiderations #re Taken 'nto #ccount Bhile $iscreti4ing The $omine )or )*%? *plain 8riefly? D&.S4 S% P#! 51 I+&%: =%#4 P#!673-675
+. *plain The #pplication ;f #$ 5 )*% D&.S4 S% P#! 5;2
