Steady state response

berktaftali · Post by **berktaftali** » Wed Sep 22, 2004 7:22 am

I'm trying the get the residual displacements in a structure after I run a nonlinear time history analysis.

The deformations Just after the ground motion ends are not the ones I'm looking for, since the structure starts free vibration with initial conditions and comes to a steady state after a while. I need to get the displacements after the structure reaches steady state.

I was letting the analysis run for 1.5 times the original length of the ground motion in the free vibration phase to get the residuals, which proved to be a very inefficient way (2.5 x analysis duration & output files).

To summarize, I need to find a way to the same thing that DRAIN2-DX command "*REST"" does, i.e. brings the structure to a static equilibrium state after a dynamic analysis.

Any ideas?

denizutkutug · Post by **denizutkutug** » Wed Sep 29, 2004 3:14 am

Hi,
Are you using raw or modified record with baseline correction? For, integration of the complete raw-time series may not result zero; leading to continuing velocity or residual displacements.
Best regards.