Distributed mass

[Layla]

Hello,
I am using nonlinearBeamColumn element and I want to assign element mass density (per unit length) in order the lumped-mass matrix to be formed.

element nonlinearBeamColumn $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag <-mass $massDens> <-iter $maxIters $tol> <-integration $intType>

The problem is that although I can do eigen analysis, I can't do time history analysis. But, if I replace the mass density with lumped masses at each node then my model runs correctly. Actually, the modes between the two models are the same (one with distributed mass and the other with lumped masses) but the time history analysis does not run if I use distributed mass..
I was wondering if there is a restriction in the use of the mass density.
Please advise..

Many thanks in advance,
Layla

[vesna]

As you noticed mass density function on a force-based element has some limitations. I would suggest you to avoid using it.

[Layla]

Thank you Vesna for your reply!