CAE Software【Femtet】Murata Software Co., Ltd.
General
The model is a bar made of viscoelastic plastic, polystyrene. It is forced to bend.
It is subjected to the temperature change below and over the glass transition temperature.
Unless specified in the list below, the default conditions will be applied.
Item |
Settings |
Analysis Space |
3D |
Model unit |
mm |
It is subjected to the temperature change below and over the glass transition temperature.
Select “Thermal load” and “Step analysis”
Item |
Settings |
Solvers |
Mechanical Stress Analysis [Galileo] |
Analysis Type |
Static analysis |
Options |
Select Thermal load. |
The Step/Thermal Load tab is set as follows.
Tab |
Setting Item |
Settings |
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Step/Thermal Load |
Step Setting |
Multi-step thermal load analysis |
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Time Setting |
Set up |
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Reference temperature |
25[deg] |
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Step/Reached Temperature Setting |
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Options for the Multi-Step Analysis |
Save the results of substeps : Select |
The reference temperature (non-stress temperature) is 25[deg]
Select [Multi-step thermal analysis] for the Step Setting, [Set up] for the Time Setting.
Also, set up in the [Step/Reached Temperature Setting].
Each step below consists of 5 substeps.
Step 1 : 60[s] : The load is increased gradually for 1 minute.
Step 2 : 3540[s] : The load is sustained for almost 1 hour.
Step 3 : 3600[s] : The load is decreased gradually for 1 minute.
Step 4 : 3660[s] : The temperature is increased to 120[deg] in 1 minute.
Step 5 : 3720[s] : The load is increased gradually for 1 minute.
Step 6 : 7200[s] : The load is sustained for almost 1 hour.
Step 7 : 7260[s] : The load is decreased gradually for 1 minute.
Save results of substeps is selected by default to output all the results at substeps.
A rectangle polystyrene plate is 0.4[mm] thick.
Body Number/Type |
Body Attribute Name |
Material Name |
0/Solid |
Plate |
PS |
The material properties for PS are set up as follows:
Material Name |
Tab |
Properties |
PS |
Elasticity |
Material Type: Elastic/Isotropic Temperature Dependency: N/A Material Property: Young’s modulus: 1.39×10^9[Pa] Poisson’s ratio: 0.35 |
Viscoelasticity |
Defined by Prony series [coefficient input] Relaxation Component: Shear only Relaxation Table:
Temperature Dependency and Shift Function: WLF Reference temperature: 113[deg] C1: 8.86 C2: 101.6
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Coefficient of Expansion |
0x10^-6[1/deg] |
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
Fix_all/Face |
Mechanical |
Displacement |
Select all X/Y/Z components. UX=0, UY=0, UZ=0 |
Pz/Edge |
Mechanical |
Distributed edge load |
Select “Set the total load”. X=0, Y=0, Z=-1.0×10^-2
Select “Time dependency” and set “Weight function” as follows. This setting means the following. 60[s] : The load is increased gradually for 1 minute. 3540[s] : The load is sustained for almost 1 hour. 3600[s] : The load is decreased gradually for 1 minute. 3720[s] : The load is increased gradually for 1 minute. 7200[s] : The load is sustained for almost 1 hour. 7260[s] : The load is decreased gradually for 1 minute. |
The deformations at 3540[sec] and 7200[sec] are shown below.
The contour indicates the displacement.
The contour diagram shows the displacement.
Deformation at 3540[s]. Temperature is 25[deg].
Deformation at 7200[s]. Temperature is 120[deg].
The deformation is larger at 120[deg], even though the mechanical load is the same as that of 25[deg].
The graph below shows the displacement of the plate tip.
The displacement is constant at 20[deg].
If unloaded, it returns to the original state.
The displacement increases at 120[deg] even though the load is constant.
If unloaded, it doesn’t return to the original state.