Description: The following procedures can now be used with user-defined interface damping: direct and mode-based steady-state dynamic analysis, including the subspace projection method; transient dynamic analysis; and complex eigenvalue extraction. For mode-based procedures the element-defined damping is taken into account only when used with the SIM architecture. The matrix and substructure generation procedures also use user-defined damping matrices via user subroutine UINTER.

In addition, the definition of the viscous damping matrix is simplified. Previously the viscous matrix implemented by the user had to be multiplied by the current circular frequency, which was supplied as an argument to the subroutine. Now the viscous damping matrix includes only the definition of the viscous damping itself.

Verification tests were added for each available procedure.