Description: Substructure damping is used to specify substructure damping factors proportional to the substructure mass and stiffness matrices at the substructure usage stage. The mass and stiffness proportional damping factors can be used in combination with the generated substructure viscous and structural damping matrices and substructure modal damping to form the substructure element damping matrix at the substructure usage stage. Substructure damping is supported in procedures where nondiagonal damping is allowed in the model domain, such as general analysis procedures, linear dynamic procedures, and the direct steady-state dynamics procedure.