Hello,
Do I need to explicitly assign nodal masses (along the relevant axis based on the anticipated direction of forcing function) for eigen value analysis in Opensees?? Or whether if I assign mass densities to the element types in the model (in Element Library) along with the lumped mass option, the nodal masses (for dead load along the vertical axis) are automatically calculated based on statically equivalent nodal gravity loads??
Regards
Tushar
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