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tjingwei October 31, 2013 05:51

[Autodyn and Explicit Dynamics]

How do I resolve overlapped mesh in Explicit Dynamics?

I had imported a complex CAD model (with many parts) into Explicit Dynamics to mesh, before exporting it to AUTODYN.

Under AUTODYN "interaction" button, I clicked on the “Check” function and it returns with “there are initial penetration".

I know this can be easily resolved if I have Design Modeler, by:
a)Group all Bodies into a single Part
b)Set the Shared Topology Method for the Part to “None”
c)In Meshing, insert Match Control objects scoped to the contact surfaces (This step may not be necessary if a single global element size is used)

I do not have DM. So is there any other method to resolve this?

Thanks in advance.

siw November 1, 2013 04:20

Since you don't have DesignModeler you should simplify the geometry in the CAD package it was made in.

I use ANSYS Explicit STR (the Workbench integrated Autodyn Lagrangian solver) and one of the first things I was told on the product demostration (the ANSYS Customer Portal has lots on explicit dynamics and it's meshing needs) was that explicit dynamics models should be simplified as much as possible (e.g. use surface and line bodies, omit parts if possible but certainly their details), mainly because the timestep (and hence simulation time) is driven by the minimum cell size.

Explicit dynamics models should not be treated like implicit FEA models, as an example see

So I don't think you should fix the overlapped mesh but rather simplify the geometry and then regenerate the mesh.

tjingwei November 5, 2013 03:08

Thank you. I will take note of that.

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