Optimization Utility FEA Error - Part boundaries not connecting

Anonymous — Wed, 17 Jul 2019 15:05:21 GMT

Hi,

I am attempting to run an optimization on a 3-part component in Netfabb. However, I am receiving this error upon attempting any simulations or optimization, including a solid sim:

FEA driver error.

Non-positive definite stiffness matrix detected in FEA model.

The simulation runs if I place restraints on all 3 bodies, but will not transmit loads between them, as seen in the screenshot below. This setup also doesn't match the load case I wish to simulate, anyways. This leads me to believe there is an issue with the meshes at the boundary between parts.

I divided the parts from a single BRep into 3 (in Fusion 360), and have not moved them relative to each other since, so their faces should line up.

I have tried meshing them to STLs at various qualities within Fusion 360, and then remeshing at various qualities in Optimization Utility. I tried importing to Netfabb as a STEP file, and meshing the bodies in Netfabb, and then remeshing in Optimization Utility at various qualities. I also tried importing to Netfabb as

a single body, and performing a plane cut to divide the regions, but this leaves a mesh that Optimization Utility deems unsuitable for FEA, and which is unable to be repaired by remeshing in Optimization Utility. I even tried making the larger part higher quality in order to approximately match triangle size with the smaller parts.

Is there anything else that might be able to fix this issue? I am willing to share files if that helps. Any advice would be appreciated. Thanks.

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Optimization Utility FEA Error - Part boundaries not connecting