nonlinear behavior of 3-D steel structures

[sharareh]

Hi there,
I'm doing my master's project by help of opensees. It is about the effect of Tuned mass damper on the earthquake induced response of 3-D steel structures. I've built both elastic and nonlinear models. There is no problem with elastic model, the results seem to be correct. But the nonlinear model (I've only changed the element type from elastic to nonlinear beam column) doesn't give proper answers. I mean even I multiply the earthquake excitation with large factors the responce in the earthquake direction remains elastic (I don't see any residual diformation). The analysis is dynamic nonlinear. I'm waiting for your urgently needed help.

[ekalkan]

Did you check your material model, what kind of material model are you using.

[silvia]

try using an elastic section with the nonlinearelement, you should get the same answer.

also, you should try a static analysis first!