Non proportional damping & complex eigen values/modes



Is there a way I can perform a modal analysis which reports complex eigenvalues (in the form a +ib). This generally occurs when the damping is NOT of the Raleigh/Ritz/Proportional type.

Kind regards,



Hi @jmassucci,

I am tagging our expert @rszoeke here. He can tell you if that can be seen in the Solver Log because I am not 100% sure about that.

For general information about the Modal Analysis have a look at: Modal Analysis - Code_Aster




Hi @jmassucci @jousefm,
currently our modal solver for structural analysis does not support any damping, so only real eigenvalues are computed.
Generally various damping types are possible with the solvers we are using, but they are currently not made available. You can add a feature request specifying which damping type would be required in our vote for features category which would help prioritizing this feature.