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Currently, the creation of displacement constraints with RBE2 ties and rotational degrees of freedom isn’t supported from the graphical user interface. To realize it, dummy loads are created and modified with by the Advanced User Settings.
On the outer cylindric surfaces two dummy loads are created. These dummy loads need to have a load value in a the direction which will be constraint afterwards.
Name | Force/Moment/Pressure/Gravity | Direction | Value in N/Nmm |
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Force 2 | Force on faces | x | 1 |
Force 3 | Force on faces | x | 1 |
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In Step 6 the dummy loads will be modified to displacement constraints with a RBE2 tie and unconstraint rotational degrees of freedom. |
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Interfaces have to be created for every functional surface - so every surface where a boundary condition is applied to. With this Tool an offset to the inside with the input “Non-Design Space Thickness” and an offset to the outside with the input “Machining Allowance” is created. The Offset Distance is expanding the Interface to the set value to create material on front faces.
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Step 6: Modifying the dummy loads to displacement constraints (with RBE2 ties)
With the Advanced User Settings the dummy loads (Load 2, Load 3) are modified to displacement constraints.
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The same is done for the second dummy load. For this, the translational displacement in x-direction is free as well.
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The optimisation parameters are selected in the Studies Area as well.
Manufacturing Method: Generic AM
Failure Criteria: Von Mises
Safety Factor: 2535
Strut Density: Medium
Shape Quality: Balanced
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Step 8: Starting the optimisation in the command line and visualize the results
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Therefore, the optimisation scenario is exported by a right click on the scenario to a freely selectable folder.
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Inside the exported folder where , all geometry information and the input configuration file for the optimisation lays a are stored. A PowerShell or command line has to be opened here.
Inside the installation folder of MSC Apex the “runGD_Engine-bat” has to be executed with the additional command (-c) for the configuration file.
& 'C:\Program Files\MSC.Software\MSC Apex\2023-009544...\runGD_Engine.bat' -c .\RotationalDoF.json
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The optimisation results can be imported back into the graphical user interface. Therefore, the Import Generative Design Results option is used. The post processing can be accessed over the new imported scenario.
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Inside the Post-Processing the von Mises stress and the displacements are visible for all iterations and for every Event
In the picture below the displacement in z-direction is displayed
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With the Mission Switch the optimised result can be analysed with MSC Apex / Nastran. The following gif shows the rotation in the created displacement constraints.
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The whole complete MSC Apex Generative Design project with all results can be downloaded here:
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