FE-Reanalysis with MSC Apex (Nastran)

MSC Apex Generative Design is a design generator. Thus, to verify the results a reanalysis with a high precise FE-Analysis Tool as MSC Apex (Nastran) should be done after deciding on a design. We recommend a reanalysis for all critical parts to include the relevant boundary & overload conditions that aren’t taken into account during an optimisation.

There are two ways to realize a FE-Reanalysis. One based on the created STL-file and another by creating a NURBS-Geometry (Retransition). For both methods an intersection has to be done to create functional sharp edges and surfaces on which the boundary conditions can be applied. This is done automatically during the optimisation for the STL-file (Nominal-Geometry) or manually with MSC Apex Generative Design for the NURBS-Geometry.

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NURBS-Geometry Workflow

1. Create a NURBS-Geometry with the Facet Body to NURBS Geometry Tool. We recommend using a non-intersected geometry for this. Therefore, the Smooth-Geometry can be exported from the Post Processing.

2. Boolean Intersection between the retransitioned NURBS-Geometry and Design Space either in MSC Apex Generative Design or MSC Apex. A tutorial how to perform a retransition here.

3. Import the NURBS CAD-file to MSC Apex.

4. Remesh the geometry with a solid mesh (Tet-elements).

5. Apply the boundary conditions

   1. Make sure that the applied boundary conditions are the same as in the optimisation (Loads are applied as RBE3 elements and fixations as RBE2 elements).

STL-file Workflow

1. Export a design candidate from the Post Processing.

   1. Make sure the intersected geometry (Nominal-Geometry) is used. Otherwise, a manual intersection needs to take place in MSC Apex Generative Design or MSC Apex.

2. Import the intersected STL-file into MSC Apex as a faceted body.

   1. Activate the “Detect Machined Faces” option.

3. Remesh the geometry with a solid mesh (Tet-elements).

4. Apply the boundary conditions:

   1. Make sure that the applied boundary conditions are the same as in the optimisation (Loads are applied similar as RBE3 elements and fixations as RBE2 elements).