September 1, 2023 at 9:11 pm
Reno Genest
Ansys Employee

Hello Ying,

For a rigid body, the axis of rotation is always through the center of mass. Here is an excerpt from the LS-DYNA User Manual Vol I for *BOUNDARY_PRESCRIBED_MOTION:

 

So, I guess the center of mass of your rigid body is aligned with the CG point correct? Have  you tried to moved the rigid body so that its center of mass is aligned with point OC for method 2?

 

Let  me know if this helps or not.

 

Reno.