This method in the video above does not work since:
1) either I can't use connections (contact step control does not work in Modal) so the two sides don't bond
2) I can use the deformed geometry with contacts, but can't use the stiffness matrix from pre-stress
My problem is that the deformation itself changes the part from two to one rigid body. Since the modal analysis doesn't bond them I can't get the correct mode shapes. But if I use just the deformed mesh and bond it, then I don't get the correct stiffness since there is no pre-stress.
Any ideas on how I can approach this problem? Thank you.