关于有限元分析教程

维分子

与大家共同讨论下关于有限元的分析.欢迎高手前来.为什么我的文件老传不上来,提示不支持扩展,搞不懂,大家先讨论,等我想法传文件.
2 ?! m4 W- E# j! L; V8 i
8 ~1 \0 s% g/ ?[ 本帖最后由 维分子 于 2008-3-28 09:08 编辑 ]

维分子

有限元分析的主要步骤
前处理
8 \0 |7 q0 w- D建立分析对象的有限元模型
5 r  T  a4 S* ^6 @7 |: {5 [, s+ `求解
4 a7 \0 u$ W3 q+ j' N对有限元模型的计算工况进行求解
后处理
. b% I& X0 [9 k2 k* g& ^观察分析结果，评估设计是否符合要求

维分子

Cosmos/Works有限元分析的步骤
建立几何模型
: ~& T3 z5 p% V6 n定义材料属性
# O9 m; f7 p, L& V3 J' [' }* q定义边界条件(约束和载荷)
! A% |# r. Y4 k  R4 p, c5 v! H划分网格
/ i/ {1 s; A/ o& V# b求解
查看和评估结果

维分子

企业需求与有限元分析
更少的样机：省钱
更短的周期：省时
5 N) p8 [7 T4 t) t5 Y# J更好的质量：品质

维分子

线性静力分析：定义专题
Displacement in the radial direction:
Select “Axis1” and then define displacement plot in X-direction (radial to the axis). Select deformation scale=1
Right-click on the displacement plot icon “plot2” and then select”List selected”
2 r$ p2 ^8 d4 K5 E8 o. g8 ~8 W' AAverage displacement of “pole piece lower” = -0.0019504” (decrease in radius)
Average displacement of “pole piece upper” = 0.007896 “ (increase in radius)
Sum of these 2 displacement = 0.009846” ~Initial interfernce of 0.01”
2 Z; e! Q/ T1 t1 I: yHoop Stress (tangential):
5 p% j0 E  n7 A6 J9 dSelect “Axis1” and then define stress plot in Y-direction (radial to the axis). Select deformation scale=1
Right-click on the stress plot icon “plot2” and then select”List selected”
Negative stress on “pole piece lower” (compression)
0 s% r1 R* q+ |& R* lPositive stress on “pole piece upper” (tension)
线性静力分析：定义材料属性
% m3 _' z3 t( p1 f# K, _! l* aSimulate parts which are separated by large gaps
First run the model with small displacement option and look at the results
If you see that there is a change in the orientation of the contact surfaces during loading or if the results doesn’t look realistic, use large deflection option

4 r% b/ H& g' Z/ |8 E1 ?- w" T& w线性静力分析：网格划分
Open “RectangleGap.sldasm”
; @$ p5 a, e& T' J6 D  @9 e4 K/ }  qDefine a static study “smallcontact”
. J: k" B' A/ d2 P, G, j7 V" PApply material “Alloy steel” to both parts
Apply a pressure of 725 psi on the top face
4 u1 Q8 I& Y+ PSelect the two front faces and then apply restraint. Select Flat face option and then select “Normal to face”
- B1 T9 x6 Q9 D" ?$ I- Q! X2 Z: o' ^; {* yFix the left semi-circular face
Hide the loads/bc symbols
Define “Surface” contact between the top face of the bottom leg and the perpendicular face
Create mesh and run
Define a stress plot with scale factor = 1. Look at the contact surface.
线性静力分析：定义约束
Define a new static study “LargeDisp”
& C! U# F/ K/ m/ \% ]: _Drag’n drop the material and loads/bc folders from “small contact” study
" n+ I# X& Y, `: [; |, ?1 P: vRight-click on the study name and click on properties. Select “Large displacement contact” option.
( [1 n: i6 b( Z; {0 I5 j9 |+ u: nRun the analysis
2 L: J4 ]" ]0 D- w8 X9 XDefine a stress plot with scale factor = 1. Look at the contact area.
线性静力分析：定义载荷
Simulate heat resistance between parts for thermal analysis
 Account for heat resistance of thin parts without actually modeling them!

; ^2 [; H% B* u6 w/ t; K% p线性静力分析：求解
) f% E/ L( `% G/ LOpen “Thermal contact resistance_transistor.sldasm”
% u) g0 P# E! _Explode the model and set preferred units to “SI” and temperature units to “Kelvin”
0 [/ ~; i& Q* p% ]3 i+ _7 ADefine a thermal study “NoRes”
$ ~: I  G+ Y* }  ]! KApply material “AISI 304” for “Voltage regulator” and “Copper” for Heat sink
Define “Surface” contact with No resistance between the contact faces
8 K4 M( t+ X. T  C# I8 V8 c5 ?% SApply convection to all the faces of the model except the contact faces
Film coefficient = 250 W/(m^2.K)
3 H$ Q. K. ^) ^5 mBulk temperature = 298 K
线性静力分析：观察结果
Apply Heat power = 25 W for “Voltage regulator”
Mesh with default settings and run the analysis
0 M# z( n# x( ?1 D0 UNotice the temperature distribution of the heat sink
Distributed Resistance:
Define a new thermal study “DistRes”
6 B0 U% u( _3 F' DDrag’n drop “Material” folder and Loads/Bc folder from NoRes study to DistRes study
! q& \0 x8 R9 S1 b7 I. x0 W! PEdit contact pair definition and define distributed resistance = 0.005 K.m^2/W
; ^. w! Q3 N1 O: Q& c0 GTotal resistance = Distributed resistance X Contact area                           = 0.005 X 0.0003392 = 14.7 K/W
Run the study “DistRes”
Notice the temperature distribution of the heat sink
% E; a- q" d% k7 n0 ~1 W% @Thermal Contact Example (Cont’d)
: ^' k. u% ?8 H) g9 BProbe the temperature value
' C0 m! j/ u, n! a6 j& H- l8 JDefine a thermal plot with mesh
Right-click the plot icon and select Probe
" r& H. A( I! k0 P3 W9 k( kPick all the nodes on the edge of both the parts
Click on the Plot icon to view the temperature variation from the top face of the voltage regulator to the bottom of the heat sink

$ o5 v0 H1 A5 N! b: J( J, UThermal Contact Example (Cont’d)
Total Resistance:
/ |, p9 v" |1 @, m7 m# b! RDefine a new thermal study “TotalRes”
, ]8 ~7 d) z/ A8 ^Drag’n drop “Material” folder and Loads/Bc folder from NoRes study to TotalRes study
5 }* a1 t: |, r  q2 Z1 G9 qEdit contact pair definition and define Total resistance = 25 K/W
& K8 g4 C( `) _% j$ s7 T* SRun the study “TotalRes”
9 }4 ~. W3 ^/ C* @7 u' E. cNotice the temperature distribution of the heat sink
! v2 b; k$ O1 G) v. ?
" V0 N1 Z% x0 u  t& F1 uLoad Simulation: Remote Loads
1 j$ U- Z  n, P; K0 p  W. g4 ARemote Loads
# N+ Y! ]3 D6 x" B$ sDirect Transfer
' e7 j1 N( M3 [1 o& S9 kFlexible surface
Applied as equivalent force & moment
Rigid Beam
Rigid surface
Remote Restraint
Rigid connection
Model effect of a rigid virtual part between two faces
! p7 i) T5 ?) E: Q2 t  g
1 U2 d9 o: E. w/ W2 q7 a& ]8 P
Remote Load Example
Open “RemoteLoadExample.sldasm”
9 o3 m* g& E  W  y7 \* sDefine a static study “Remote”
Apply material “Alloy steel”
8 s  k' ]% n: G6 ]Fix the flat face
Select “Coordinate system1” and the end face of the cantilever. Define remote load of 10N in the X direction.
Create mesh and run.
Double-click on “Plot1” under the stress folder
. d' d9 U0 r" h2 A- L- j% G9 RAnimate the results
Compare the plot results of “Remote” study with “Axial Tension” study
! j# B; J+ K7 }3 d4 }0 L
5 u# ^/ S! q+ E1 HMotion Load Transfer Using Remote Loads
Go to SW Add-in and click “COSMOS/Motion”
Open “LoadTransferModel_With_Result.sldasm”
Play the animation and save the load file for frame # 300
Delete the motion results
! V! V0 S: X' A$ y5 R# Q) n- S+ C/ RGo to CW menu, Import Motion Load and open this load file from “MotionLoadTransfer” directory
, O. @$ w/ B. DSelect all the loads related to crank-1 and then click OK.
  h; j7 L% ^1 \- r2 v, QOpen the part “crank”
: T. y" F2 i; K8 A8 i$ r- X4 t$ ~3 CYou’ll see that there is a new study “Frame-300” with motion loads transferred as remote loads
Apply material “Plain carbon steel”
: }' k) ]7 W& Z* NGo to study properties and select “FFEPlus” solver and “Inertia relief option”
Run the analysis
# R$ }' a+ {) w: s! \) h: y) {  e8 nPostprocessing: Results in local CS
Plotting
Listings
Reaction forces
Postprocessing: Exploded views
Plot results on SolidWorks exploded views
1 l" w* o& Q9 k
Postprocessing: New tools
  s: `9 I0 ?1 l' bImproved probing with graphing option
7 V0 @* N! `- yList results by Entity
/ e  T: i. a: SWeb Reports
3 @8 L' E8 ]3 w& w* W5 s, CInclusion of report templates in the feature tree
3 S- I2 H& l; v+ y) KSaving of report setting
Automatic creation of all plots
# @1 }+ P% U; I% t$ }7 P6 o) _Report Example
Open “ReportExample.sldasm”
New option save JPEG files (Right-click on the Study name)
* J/ ]" T$ e# ]Right-click on Report and click define
% a  W/ v% [) n- N/ a5 D- U: G% ]Point to the logo file “ReportLogo.bmp”
Point to the right stress AVI and VRML files
Select option “Automatically update all plots in JPEG files”. Click OK.
0 f/ m& n0 K5 i* \You can also get a print version
8 V0 o$ d- h! t' }& pMaterial
Supports orthotropic material properties for solids and shells
Option to use different Material library files
New redesigned material browser utility

& X  m9 N( W7 h* P1 V1 U" l  v* A- PLicensing
Single license file for hardware lock & FlexLM security
New License Administrator to manage the license
; U# X! c2 b0 ISupport USB port hardware lock
Support redundant servers
. ~( ?; w/ a: P" h" N( F
8 k8 q) T5 S# l  nOther customer enhancements
! }$ Z/ _0 q( ?* ?/ TAutomatically run analysis after meshing
Edge pressure for shells
Apply uniform temperature to components
3 w* F, p/ n5 Z: _9 t# a$ M6 h# I7 OAutomatic adjustments of Max & min in plots on update
FFEPlus solver for thermal analysis
3 T" [( f3 z$ X" g" `* [# u4 |1 KIncrease the limit on number of modes for frequency analysis from 20 to 100
- U# i; O  h1 ]% R( OAdd symbol for gravity loads
Improve section clipping
Save plots in JPEG format
Improve transient thermal animations
Option to switch between different languages
Others…

' a# \/ ^% U! E# aThank You!