CAE Software【Femtet】Murata Software Co., Ltd.
General
Axisymmetric analysis is applied as we deal with a shape like curved saucer.
Item |
Setting |
Analysis Space |
Axisymmetric |
Model unit |
mm |
It is necessary to take rotation of elements into account strictly to simulate the reverse warping of the bimetal. Therefore, select “Large displacement” in “Large deformation”.
Item |
Setting |
Solvers |
Mechanical Stress Analysis [Galileo] |
Analysis Type |
Static Analysis |
Large Deformation |
Select Large displacement |
Options |
Select Thermal load. |
The Step/Thermal Load tab is set as follows.
Select “Multiple steps” and set the reached temperature to keep history of temperature changes.
Tab |
Setting Item |
Setting |
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Step/Thermal Load |
Step Setting |
Multi-step thermal load analysis |
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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 |
Setting on the High-level setting tab is as follows.
Tab |
Setting Item |
Settings |
High-level setting |
Nonlinear analysis |
Converge the steps forcibly and continue analysis |
To form two models, create two arcs with diameter of 100[mm] and angle of 5°. Stretch them by 0.01 in Z direction.
As a combination of different thermal expansion coefficients, set material properties of copper and stainless steel (SUS410) for each body.
Set the boundary condition on the edge of lower body with displacement in Z direction fixed.
General mesh size is 0.1[mm]
Body Number/Type |
Body Attribute Name |
Material Name |
0/Solid |
CU_PLATE |
008_Cu (*) |
1/Solid |
SUS_PLATE |
518_SUS410 (*) |
(*) Available from the Material DB
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Setting |
zFix/Face |
Mechanical |
Displacement |
Select the Z component |
At the end of the analysis, a message will appear saying “Warning: Converged the nonconverged steps forcibly and continued analysis.” But the results can be shown.
In the list of modes below, [Forced convergence] is shown at the results of 80th (126.25℃) and 81st (127.50℃) steps since these did not converge.
The diagrams below show the deformation at 79th (125℃) and 82nd (128.75℃) steps before and after the forced convergence.
The contour is the displacement in Z direction.
[Full Model] is selected for viewing.
The deformation up to 125℃ is small and the shape is almost the same as the original shape. At 128.75℃, its central area is observed to bend in -Z direction.
Buckling is considered to be taking place between 125℃ and 128.75℃.
The displacement is plotted in the diagram below with temperature on horizontal axis.
When the temperature is rising, the displacement in -Z direction at temperature beyond 125℃ is rapid while it is gentle below 125℃.
When the temperature is falling, the displacement in +Z direction at temperature below -32.5℃ is rapid while it is gentle until -32.5℃.
Hysteresis of the different behaviors in the temperature rise and fall is analyzed.