how to define spring stiffness and damping coefficient of different Joints

Dear Sir/Madam

How to fix spring stiffness and damping coefficient of different Joints.

I have designed a cad model in simmechanics but I am unable to fix the damping and stiffness of different joint with increasing mass, because of that my model is showing unstable behavior. Kindly suggest me what method I should have to follow for fixing of this instability problem.

I will be highly obliged if you can share some paper or video or techniques or mathematical methodology for fixing the internal mechanics like Spring Stiffness , Damping coefficient different joint (like spherical joint, revolute joint, cylindrical joint, prismatic joint etc.).

Thanking You Sanjeev