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Why does my part moves against gravity in Nonlinear transient once it contacts rigid mesh

Hello,

I am trying to do a Non linear transient simulation on a sheet metal that contacts a rigid mesh only with gravity loading. The sheet metal seems to be moving in the right direction and contacts the part correctly, but once it has contact with the rigid mesh it moves upward and even though the solution converges, the movement of the sheet metal does not make any sense. Could anybody explain why it does that or what can I do to stabilize the solution?

Thanks for your help.

Natalia Reynoso

gravity_test1.fem

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OptiStruct

v2021.2

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Rajashri_Saha

Hi Natalia,

I think you should apply Gravity load by defining a local co-ordinate system as the components are not in global view. I just updated it and now the behavior is correct.

See the attached fem.

Thanks

Rajashri

gravity_test1_CID.fem

Natalia Reynoso

Hi Natalia,

I think you should apply Gravity load by defining a local co-ordinate system as the components are not in global view. I just updated it and now the behavior is correct.

See the attached fem.

Thanks

Rajashri

Hi Rajashri,

Thanks for your reply. My model is actually in global view, and the gravity should be in global -z direction, so when the sheet metal contacts the angled surface, it stops from falling with the contact with the pin. I took your .fem and changed the direction to -z in global for the gravity and I keep having the same separation. Do you have any suggestion? Thanks,

Natalia Reynoso