Ansys Lab Manual Bvcoek

 

 

Finite Element Analysis Analysis Lab

BHARATI VID BHARATI VIDY YAPEETH’S APEETH’S COLLEG COLLEGE E OF ENGINEERING, KOLHAPUR 

Department o !e"#an$"a% En&$neer$n&

F$n$te E%ement Ana% Ana%'($( '($( La) !an*a%

Final Year Engineering

Department of Mechanical Engg.

Page 1

 

 

Finite Element Analysis Analysis Lab

Term +or./ One assignment on past, present and future of FEA.

0/ One assignment on Meshing – types of elements, choice of element, type of meshing – 

automatic, mapped, meshing in critical areas.

1/ Finite Element Analysis of Steppe2 )ar (To or Three !teps only"

using a" Finite Element Approach (Theory"  #" Finite Element !oftare (A$!Y! % A&A'! % $)!A % $A!T*A$ etc." c" 'omputer +rogram using ' or ' 'ompare the results #y a#o-e three methods in ta#ular form.

3/ se of any O$E !tandard softare pacages lie A$!Y!, $)!A, $A!T*A$,

/Y+E*0O*! /Y+E* 0O*! for sol-ing sol-ing folloing types of pro#lems ith snap shots of  softare ( Any F)2E" 3

!tatic Analysis of Truss

3

!tatic Analysis of &eam

3

!tatic Analysis of +late ith a circular hole

3

!tatic Analysis of 0all &racet

3

&ucling Analysis of 'olumn

3

Analysis of 14 or 54 Fin Fin

Department of Mechanical Engg.

Page 5

 

Finite Element Analysis Lab SL/ NO

 

T$t%e

1.

+erforming a Typical A$!Y! Analysis

5.

6eneral !teps

7.

+ast, +resent and Future of FEA

8.

4iscreti9ation of the pro#lem

:.

!tatic Analysis of !tepped &ar 

:.

!tatic Analysis of Truss

;.

!tatic Analysis of &eam

.

Pa&e No/

  Analysis of 14 or 54 Fin

Department of Mechanical Engg.

Page 7

 

Finite Element Analysis Lab

Gett$n& Starte2 4$t# ANSYS Perorm$n& a T'p$"a% ANSYS Ana%'($( The A$!Y! program has many finite element analysis capa#ilities, ranging from a simple, linear, linear, static analysis to a comple?, comple?, nonlinear, nonlinear, transient dynamic analysis. The analysis guide manuals in the A$!Y! documentation set descri#e specific procedures for   performing analyses for different diff erent engineering disciplines. A typical A$!Y! A$!Y! analysis has three distinct distinct steps@ &uild the model. Apply Ap ply lo load adss an and d o# o#ta tain in th thee solution. *e-ie the results.

B*$%2$n& a !o2e% &uilding a finite element model reuires more of an A$!Y! userBs time than any other   part of the analysis. First, you specify a Co#name and analysis title. Then, you use the +*E+< +*E+ <  preprocessor to define defi ne the element types, element real constants, material properties, and the model geometry. Spe"$'$n& a 5o)name an2 Ana%'($( T$t%e This tas is not reuired for an analysis, #ut is recommended . De$n$n& t#e 5o)name The jobname The  jobname is a name that identifies the A$!Y! Co#. 0hen you define a Co#name for an analysis, the Co#name #ecomes the first part of the name of all files the analysis creates. (The e?tension or suffi? for these filesB names is a file identifier such as .4&." &y using a Co#name for each analysis, you insure that no files are o-erritten.

)f you do not specify a Co#name, all files recei-e the name  FILE or  file  file,, depending on the operating system. 'ommand(s"@6FI LE LE NA !E 6)@ Ut$%$t' !en*7F$%e7C#an&e 5o)name De$n$n& E%ement T'pe( The A$!Y! element li#rary contains more than 1DD different element types. Each element type has a uniue uniue num#er and a prefi? that identifies the element category@ & EAM8 , + A$E

 

Finite Element Analysis Lab

All structures in the real orld are three dimensional hoe-er appro?imation are made to facilitate simple stern analysis of a part #y assuming plane stress or plane strain conditions. &odi &o dies es hich hich are are lo long ng K hos hosee ge geom omet etry ry K load loadin ing g do donN nNtt -a -ary ry sign signif ific ican antly tly in the the longitudinal direction can #e modeled #y using a plane strain representation for e?ample, Analysis of  dams K spline shaft. !imilarly, #ody is that ha-e negligi#le direction in one direction can #e assumed to #e in a plane stream condition e.g asher. 0here a geometrical appro?imation is not possi#le then full 74 model of the structure structure ill need to #e de-elop although although it might still #e possi#le possi#le to limit the si9e of the model #y taing ad-antage of any symmetry that the pro#lem e?hi#it. 1. !implification through symmetry a" A?ial symmetry !ince a?ial symmetry is encountered so freuently a?is symmetry elements are included in finite element pacages. They tae account of the constant -aria#le distri#ution in the circumferential direction.  #" +lanar symmetry 'onsider a flat plate ith a hole in it loaded uniformly as shon in fig. it is only necessary to consider one uarter of the pro#lem pro-ide that correct constraints conditions are applied to model c" 'yclic !ymmetry 'yclic symmetry is present in spline fitting K propellers the pro#lems are similar to those str struct ucture uress model model assumin assuming g plane plane str strain ain system system for repetit repetiti-e i-e symmet symmetry ry pro pro#le #lem m the com common mon  #oundries of the repeated segment are constraints constraints in a perpendicular direction. 5" &asic element shapes

S#ape

T'pe

+oint

Mass

ine

!pring, #eam, spar, gap

Area

54 solid a?is symmetry

'ur-ed ar area

!hell

Geometr'

!hell elements are of the special category #ecause they do not refall for either area or -olume type. They are essentially 54 in nature #ut are de-eloped so that can #e used to model cur-e surfaces. 7" 'hoice of element type 0hile selecting element type first step is to analyses the gi-en pro#lem for unnon -aria#les K #oundary conditions (constraints" K secondly s econdly chosen dimensionally of model. 8" !i9e K no. of element are clearly in-ersely related. As no. of elements increases si9e of each element decreases K conseuently of the model increases.

Department of Mechanical Engg.

Page 1D

 

Finite Element Analysis Lab

For e?ample, a thermal analysis of cooling fins here an e?act solution shos that temp. -aries in uadratic manner. )f simple 14 elements are used that assume a liner -ariation in temp. then finite element method can #e seen to reduce a procedure of appro?imating the cur-e distri#ution shell ith another of straight line. Fig. shos ho the accuracy of analysis increases ith increase element num#er.. As no. of elements approaches ith e?act solution as shon in graph. num#er :" Element shape K distortion 

Finite element method works by approximang approximang the distoron of unknown variable



in precise manner across the body to be analyze. However these distribuons are only reliably produced if the shapes of elements



are not excessively distorted. As element distoron increases errors in formulaon start to become increasingly



important. Hence the elements should be as regular as possible allowable limit of distoron are dicult to uan!ed " depend very much on variable distoron. #ne measure of element distoron is aspect rao.   $ongest side of element Aspect rao % &hortest side of element   Aspect ratio for rectangle  

'

%()'%'.(

7

7%71

  (  Aspect rao for suare*

 

7

Alterna Alte rnatiti-ee method method of assessi assessing ng elemen elementt distor distortion tion is to conside considerr int intern ernal al angles angles of ele elemen ments. ts. *ectangular element angle as close to >D ° as possi#le for triangular elements should #e near to ;D  °.

!omee commer !om commercia ciall finite finite elemen elementt pacag pacages es perfor perform m distor distortio tion n checin checing g for user user typica typically lly #y calculating aspect ratio of the elements. )f -alue are found to #e distorted #ut ithin predetermining limits. /oe-er if elements are grossly distorted the programme stops K proceed only ith specific authori9ation from user. ;" ocation of nodes

Department of Mechanical Engg.

Page 11

 

Finite Element Analysis Lab

 

0hen modeling modeling a pro#lem pro#lem the user needs only on di-ision di-ision of geometry geometry into element element so that

-aria#le distri#ution is adeuately represented. Therefore, of nodes any changes in material properties geometry #oundary condition K loads.  

The stiffness matri? of each element depends on material properties of that region in model

therefore a line of nodes ill alays reuired at interface of different material.  

)f there is an a#rupt change in cross sectional area or discontinuity in 54 or 74 models from a

crac possi#le ould need of nodes defining gap in materials.  

0hen a concentric load is applied then there must a node at corresponding position in finite

element model or if a distri#uted load is present then nodes must define start K finish position of load.  

'orresponding case in stress analysis of toothed gear in hich a force acting on surface of 

 #ody location of nodes are shon in fig. fig. 'onsider e.g of 5 plane stress model of a #eam as shon in fig. the 5 models are same e?cept node num#ering hich la#el either hori9ontally or -ertically. From models ith hori9ontal la#eling e can see that the degree of freedom associated ith nodes 1 K > ill #e related since they occur in same element. /oe-er in model ith -ertical la#eling node no. 1 related to node no.;. $o since models are 54 each node ill ha-e 5 degrees of freedom. First 5 columns K 5 ros of matri? ill correspond to node ;. !imilarly, in hori9ontal la#eling node n.> ill correspond to 1< th  K 1=th ro K column. /ence si9e of matri? ill increase. )n general #andidth is calculated #y &(41"f here 4  largest diff. #eteen nodes of single element K f is degree of freedom. )t is o#-ious from a#o-e e?ample the nodes should #e num#ered across shortest dimension to achie-e smallest nodal difference in any one element. The a-e front method ne-er constructs hole stiffness matri? instead it eliminates the degree of freedom hen it ors through the model. 0hen last occurrence of node is noted its degrees of freedom are eliminated out of matri? for e.g. stiffness matri? of element no.1 is calculated K placed into temp. Matri?. !ince nodes 1 occurs in the first element it ill not #e referred #y any other element element K it can #e remo-ed remo-ed from matri?. Thus means that the degrees of freedom associated associated ith node 1 are ritten as function function of degrees of of freedom of nodes 5, :, ;. Element 5 is considered considered ne?t its stiffness matri? is calculated K added into temporary matri?. $ode no. 5 ill not #e referred  #y any other element K can #e remo-ed hence at this point 7,:,;,< is held in matri?. This process continues through all elements until only node no. 5= is left K its degree of freedoms are sol-ed. Then  #acard su#stitution occurs K all other degree of freedom are e-aluated num#ering should #e across shortest dimension of model. 

./ Steppe2 Bar Ana%'($( Con($2er t#e (teppe2 )ar (#o4n $n $&*re )e%o4/ Determ$ne t#e No2a% D$(p%a"ement, Stre(( $n ea"# e%ement/

Department of Mechanical Engg.

Page 15

 

Finite Element Analysis Lab

Step .- An('( Ut$%$t' !en*

File – clear and start ne – do not read file – o – yes. Step 0- An('( !a$n !en* 9 Preeren"e(

select – !T*'T*A – o  Step 1- E%ement

Element type – Add%Edit%4elete – Add – in – 74 finite strain 1=D – o – close. *eal constants – Add – o – real constant set no – 1 – c%s area – 7DD – apply – real constant set no – 5 – c%s area – 5DD – o – close. Step 3- !ater$a% propert'

Material +roperties – material models – !tructural – inear – Elastic – )sotropic – EG – 5e: –+*GY D.7D o – Material – $e model – 4efine material )4 – 5 – o – !tructural – inear – Elastic –  )sotropic – EG – D. –o –o – close. !ection– #eam – common section – rectangular – &8D K /;D –o. Step ;- !o2e%%$n&

Modeling – 'reate –eypoints – )n Acti-e '! – eypoint no.1(D,D,D" Apply (first eypoint is created"  – eypoint no.5(15DD,D,D" no.5(15DD,D,D" – o  'reate – ine – ines – straight lines. – pic eypoint 1 K 5 – o Meshing – mesh attri#utes – piced lines – select line l ine – o  !i9e control – manual si9e – glo#al – si9e – element edge length – : – o  Meshing – mesh lines select line – o  Step

 

Finite Element Analysis Lab

  m   m    A    A    .

.; N

 

;mm

;mm

;mm

Step .- An('( Ut$%$t' !en*

File – clear and start ne – do not read file – o – yes. Step 0- An('( !a$n !en* 9 Preeren"e(

select – !T*'T*A – o  Step 1- E%ement

Main menu – +reprocessor – element type – add – shell –7d node 1=1 – close Step 3- !ater$a% propert'

Main menu – +reprocessor – material prop – material models – structural – linear – elastic – isotropic – enter EG  5e: K +*GY  D.7D – o  Main menu – +reprocessor – sections – shell – layup – add%edit%delete –thicness1D mm – o  Step ;- !o2e%%$n&

Modeling – 'reate –eypoints – )n Acti-e '! – eypoint no.1(D,D,D" Apply (first eypoint is created"  – eypoint no.5(1:D,D,D" no.5(1:D,D,D" – o– eypoint no.7(1:D no.7(1:D,1DD,D" ,1DD,D" – o– eypoint no.5(D,1DD,D" no.5(D,1DD,D" – o  +reprocessor – Modeling – create – areas – ar#ritary – through  eypoints eypoints –  !elect eypoints 1,5,7,8 – o  +reprocessor – Modeling – create – areas – circle – solid circle – circle 1(:D,:D" K radius1: mm –  circle 1(1DD,:D" K radius1: mm – o  +reprocessor – Modeling – operate – #ooleans – su#tract –areas – select rectangle – select to circles– o  Department of Mechanical Engg.

Page 5D

 

Finite Element Analysis Lab

Meshing – mesh attri#utes – piced area – select rectangle – o  !i9e control – manual si9e – glo#al – si9e – element edge length – 5 – o  Meshing – mesh – areas – free – select rectangle – o  Step / Po(t Pro"e(($n&-

(a" 6en. post processor – plot results – contour plots – $odal solu – stress – -on mises – o  !imilarly for principal stresses  GGGGG 

T#erma% Ana%'($( o F$n A%*m$n*m $n( K  = +6m,  0> &6m1, C  >= 56&K are "ommon%' *(e2 to 2$(($pate #eat rom 8ar$o*( 2e8$"e(/ An eamp%e o a (e"t$on o a $n $( (#o4n $n $&*re )e%o4/ T#e $n $( $n$t$a%%' at a *n$orm temperat*re o 0>C/ A((*me A((*me t#at (#ort%' ater t#e 2e8$"e $( t*rne2 on, t#e temperat*re o t#e )a(e o t#e $n $( (*22en%' $n"rea(e2 to ?C/ T#e temperat*re o t#e

Department of Mechanical Engg.

Page 58

 

Finite Element Analysis Lab

(*rro*n2$n& $( 0>C 4$t# a "orre(pon2$n& #eat tran(er "oe$"$ent o #  1 +6m0K/ So%8e t#e pro)%em *($n& ANSYS/

Step .- An('( Ut$%$t' !en*

File – clear and start ne – do not read file – o – yes. Step 0- An('( !a$n !en* 9 Preeren"e(

select – Thermal – o  Step 1- E%ement(

+reprocessor  element type (plane::"  o 



add



add



thermal



solid



uad 8node

Step 3- !ater$a% Propert$e(

Main menu  +reprocessor  material properties  material models  material model 1  thermal  conducti-ity  isotropic  enter GG  D  o 

Step =/ So%*t$on-

Main menu – !olution – sol-e – current ! Step >/ Po(t Pro"e(($n&-

6en. post processor  plot results result s  nodal solu



4OF solu  temperature  o 

 GGGGG 

Department of Mechanical Engg.

Page 5;