FreeCAD: Stress Analysis (3/3)
Viewing result
Select "CCX_Results" in model tree and click FEM results
to show result view dialog.
First we view the deformation. Select "Displacement Magnitude" on task tab to show deformation as color. Large deformations are shown in red, and small deformations are shown in green.
And minimum and maximum value of deformation will be shown on task tab. In this analysis, we find that the minimum value is zero and the maximum value is 6.95 mm.
Then we view the actual deformation. Check "Show" on task tab and set "Factor" to 5. Now the shape will be deformed by five times its actual size.
Next we view the sress. Select "von Mises Stress" to show von Mises Stress (equivalent stress) as color.
And minimum and maximum value of the Mises Stress will be shown on task tab. In this analysis, we find that the minimum value is 3627.49 Pa and the maximum value is 74.27 MPa.
In this analysis, we use ABS as the material, and the yield stress (tensile yield stress) of ABS is generally around 35 MPa to 59 MPa. As a result of the analysis, the maximum stress was 74.27 MPa, which indicates that irreversible deformation occurs in this shape. When we view the Mises stress distribution, we can see that the stress is concentrated in the L-shaped corner where be painted with red. Therefore, we try to improve the shape to avoid the concentration of stress.
Shape improvement and checking the results
Double-click "Sketch" in model tree to edit the sketch which the shape based on.
Click "R 5 mm" for radius at the corner and change the radius to 30 mm.
When sketch editing is finished by clicking on task tab, the mesh will be automatically recreated.
Switch workbench to FEM workbench
and delete result
to remove old calculation result. Then Double-click "
SolverCcxTools" and re-run the calculation.
When the calculation is finished, select FEM results as before to check the deformation and stress.
The maximum value of deformation decreased from 6.95 mm to 4.89 mm.
The maximum value of Mises stress decreased from 74.27 MPa to 46.90 MPa and is about 40 % lower. It's not perfect yet, but it's stronger for the load than the first shape.
Saving and Loading Analysis
When you save the FreeCAD document as file, all analysis data will be saved to the file. And if you read the file that include analysis result, you should right-click the analysis in model tree and activate it to view the calculation result.
