Damping in nonlinear time step analysis


I have been running a time step analysis in ASE (seismic analysis). The model consist of a concrete structure that is supported and connected by nonlinear springs. In the analysis, seismic motions are applied at the supports representing an earthquake. Se code in ASE below.

The analysis should include a relative damping ratio of 5 % for the structure. I have tried to include damping in the analysis by adding “GRP NUMBER MODD 0.05” for the structure, but damping is not included in the analysis. How can I include a relative damping ratio for the concrete structure in the analysis? Is it not possible to apply “GRP NUMBER MODD 0.05” for time step analysis?

Br. Jakob


please use mass and stiffness proportional damping.
GRP 1 RADA ??? RADB ???

See chapter GRP in ASE manual and chapter MODD in DYNA manual. In DYNA manual you will find an explanation how to evaluate mass and stiffness proportional dampinkg values.

Thank you