I am solving the eigen value analysis where my model assembled with two different parts, i should have to give kinematic coupling over intersecting nodes of different parts.my particular nodes should not move in x , y-directions and free to move in rotations. I mover over i am applying spring at intersecting nodes of two parts- in this case x,y and rotations all are constrained at nodes i need to give rotational spring stiffness 6 DOF.
I have tried with kinematic coupling over two sets of nodes- I found error as following = THREE FACTORIZATIONS IN A ROW FAILED. CHECK THE MODEL. IT IS POSSIBLE THAT THE MODEL CONTAINS THE KINEMATIC COUPLING DEFINITION SET UP IN A WAY THAT A DEGREE OF FREEDOM HAS NEITHER MASS NOR STIFFNESS.
I need brief explanation how to give this constraints over the joints.