Reno Genest
Ansys Employee

Hello Ying,

Does the rigid body rotate about its center of mass? If so, then the behavior is correct. If not, then something is wrong. The rigid body should rotate about its center of mass.

Also, you mentioned the following:

Tried the constraints in *MAT_RIGID, the rotation is different from without constraints in *MAT_RIGID. The result with constraints is the correct one, right?"


I don't know which one is correct; it is for you to decide. Is the behavior what you want? 


I suggest you build a small model to test the keywords. Once you are satisfied with the behavior, implement the settings on the real model.


Note that Ansys employees are not allowed to upload or download files on the Ansys Forum. You can still post your model and another user may be able to help you.


Let me know how it goes.