DMIG matrices in complex eignevalue problem and frequency response

Hi all,

I have a Nastran bdf model with the following DMIG matrices: complex asymmetric stiffness matrix (K2PP), asymmetric damping matrix (B2PP) and symmetric mass matrix (M2PP). I need to use such model for complex eignevalue analysis and frequency response function computation in Optistruct.

Can you tell how can I import such model in Optistruct and what solutions are compatible with such matrices?

Do you know if Optistruct accepts a K2PP matrix with complex valued matrix elements?

Thanks,

Simone