Problem with Coupling Constraint leading to Rigid Body of rotated part

[Breadmon1818]

Hi Forum, I have a very simple model representing a ball and socket. I aim to simulate internal socket movement by placing the ball and socket in contact and then adding a small displacement to the ball to create a stress distribution in both rudiments, followed by a rotation of the ball about its center point.
(A frictionless, "Hard Contact" surface-to-surface contact interaction is used between the outer surface of the ball and the inner surface of the socket. The simplified socket is fixed on its top (distal end) and on its sides).

Unfortunately, when rotating the ball about its center a constraint is needed (I've used coupling primarily but have tried MPC, Tie, and others) which then considers the ball rudiment as a rigid body. With this constraint, rotation is achieved, however, no stresses are developed for the ball rudiment ... the developed stresses are what I am aiming to find/use for continued analysis.

I've read the theory behind these constraints and am aware that constraining a surface, node(s), or geometry to a specific reference point (in my case the center of the ball rudiment) means that the moments/forces/stresses of the reference point will be distributed to that of the constrained surfaces/nodes, etc.
This explains why the ball rudiment acts as a rigid body and thus no stresses occur, but is there any way around this issue?
Is there a way to achieve the same rotation about the center of the ball (in a rotational BC) without making the ball rudiment rigid?

 

[FEA way]

Can you share a picture of this model ? Is there no shaft attached to that ball ? The easiest way would be to apply a constraint to its end without having to make the whole shaft rigid.

 

[oldNail]

I suggest defining a spherical partition or surface near the core of the ball and use that in the definition of your rigid body or coupling. Having the rigid elements small and far away from the interaction you're interested in will minimize their effect on the results.

 

[Breadmon1818]

Was able to work around this and develop a solution.

 

[Breadmon1818]

Thank you for the responses! oldNail this is similar to what I did and it works for my analysis!