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fmk wrote:
> why don't you use an Elastic section to find how were you are messing up ..
> and instead of doing a model with multiple elements, just look at a
> cantilever.

Thanks for your help. I have solved it.

Hello~~ I have made two models with different section command. One is a 3story 3bar steel frame in which the cross-section is defined by "aggregate" command. The other one is defined by fiber section. Even though I have used the same cross-section, the two models' eigen values were extreme...

fmk wrote:
> because there is still some rigid bod modes, translational dof nodes 3 and 4.

you mean that the translational dof nodes 3 and 4 have been constrained.
I'm a beginner, could you please make it correctly for me?

Hello,everybody. I have just tried to use the zerolength element to simulate a rotation friction damper. But I don't know why it can not be worked. WARNING BandGenLinLapackSolver::solve() -LAPACK routine returned 8 DisplacementControl::newStep(void) - failed in solver StaticAnalysis::analyze() - the...

Thank you for your kindly reply .
The problem has already be solved by opensees version 2.4.1 .
But to my surprise, the version 2.4.6 cannot work on it.

hello I built up the 2D steel frame with rotational friction damper by rotspring.tcl. However，it does not work while I use the time history analysis. the warning message is belows: WARNING: CTestNormDispIncr::test() - failed to converge after: 1000 iterations NewtnRaphson::solveCurrentStep() -the Co...