关于有限元分析教程

vidrxua

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.

blueligting

有限元分析的主要步骤
前处理
建立分析对象的有限元模型
求解
对有限元模型的计算工况进行求解
后处理
观察分析结果，评估设计是否符合要求

ωǒ是Vek

Cosmos/Works有限元分析的步骤
建立几何模型
定义材料属性
定义边界条件(约束和载荷)
划分网格
求解
查看和评估结果

sdzx

企业需求与有限元分析
更少的样机：省钱
更短的周期：省时
更好的质量：品质

huzhihua

   经典案例图书

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”
Average 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”
Hoop Stress (tangential):
Select “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)
Positive stress on “pole piece upper” (tension)
线性静力分析：定义材料属性
Simulate 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
线性静力分析：网格划分
Open “RectangleGap.sldasm”
Define a static study “smallcontact”
Apply material “Alloy steel” to both parts
Apply a pressure of 725 psi on the top face
Select the two front faces and then apply restraint. Select Flat face option and then select “Normal to face”
Fix 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”
Drag’n drop the material and loads/bc folders from “small contact” study
Right-click on the study name and click on properties. Select “Large displacement contact” option.
Run the analysis
Define 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!
线性静力分析：求解
Open “Thermal contact resistance_transistor.sldasm”
Explode the model and set preferred units to “SI” and temperature units to “Kelvin”
Define a thermal study “NoRes”
Apply material “AISI 304” for “Voltage regulator” and “Copper” for Heat sink
Define “Surface” contact with No resistance between the contact faces
Apply convection to all the faces of the model except the contact faces
Film coefficient = 250 W/(m^2.K)
Bulk 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
Notice the temperature distribution of the heat sink
Distributed Resistance:
Define a new thermal study “DistRes”
Drag’n drop “Material” folder and Loads/Bc folder from NoRes study to DistRes study
Edit contact pair definition and define distributed resistance = 0.005 K.m^2/W
Total 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
Thermal Contact Example (Cont’d)
Probe the temperature value
Define a thermal plot with mesh
Right-click the plot icon and select Probe
Pick 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

Thermal Contact Example (Cont’d)
Total Resistance:
Define a new thermal study “TotalRes”
Drag’n drop “Material” folder and Loads/Bc folder from NoRes study to TotalRes study
Edit contact pair definition and define Total resistance = 25 K/W
Run the study “TotalRes”
Notice the temperature distribution of the heat sink
Load Simulation: Remote Loads
Remote Loads
Direct Transfer
Flexible surface
Applied as equivalent force & moment
Rigid Beam
Rigid surface
Remote Restraint
Rigid connection
Model effect of a rigid virtual part between two faces
Remote Load Example
Open “RemoteLoadExample.sldasm”
Define a static study “Remote”
Apply material “Alloy steel”
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
Animate the results
Compare the plot results of “Remote” study with “Axial Tension” study
Motion 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
Go to CW menu, Import Motion Load and open this load file from “MotionLoadTransfer” directory
Select all the loads related to crank-1 and then click OK.
Open the part “crank”
You’ll see that there is a new study “Frame-300” with motion loads transferred as remote loads
Apply material “Plain carbon steel”
Go to study properties and select “FFEPlus” solver and “Inertia relief option”
Run the analysis
Postprocessing: Results in local CS
Plotting
Listings
Reaction forces
Postprocessing: Exploded views
Plot results on SolidWorks exploded views
Postprocessing: New tools
Improved probing with graphing option
List results by Entity
Web Reports
Inclusion of report templates in the feature tree
Saving of report setting
Automatic creation of all plots
Report Example
Open “ReportExample.sldasm”
New option save JPEG files (Right-click on the Study name)
Right-click on Report and click define
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.
You can also get a print version
Material
Supports orthotropic material properties for solids and shells
Option to use different Material library files
New redesigned material browser utility
Licensing
Single license file for hardware lock & FlexLM security
New License Administrator to manage the license
Support USB port hardware lock
Support redundant servers
Other customer enhancements
Automatically run analysis after meshing
Edge pressure for shells
Apply uniform temperature to components
Automatic adjustments of Max & min in plots on update
FFEPlus solver for thermal analysis
Increase the limit on number of modes for frequency analysis from 20 to 100
Add symbol for gravity loads
Improve section clipping
Save plots in JPEG format
Improve transient thermal animations
Option to switch between different languages
Others…
Thank You!