zeroLengthContactNTS2D element and warning

[khatibi_m]

Dear Dr Silvia

I modeled soil-structure interaction. I model soil and foundation by quad element and elasticBeamColumn element, respectively. in ground level, I define three group elements (soil node, virtual node and foundation node) in same coordinate. virtual nodes have tow degree freedom in x and y direction. virtual nodes and foundation nodes were tied in x and y direction by equaldof comment. I used zeroLengthContactNTS2D element for slipping between soil and virtual nodes. I used nonlinear dynamic analysis for model.
first I did a eigenvalue analysis, and structure periods were acceptable. but when I did nonlinear dynamic analysis for model, this warning was displayed:
"""""
WARNING: CTestNormDispIncr::test() - failed to converge but going on - current
Norm: 0.0171762 (max: 0.01, Norm deltaR: 308.865)
WARNING: CTestNormDispIncr::test() - failed to converge but going on - current
Norm: 539889 (max: 0.01, Norm deltaR: 5.06599e+009)
""""""
which is warning?

[fmk]

does convergence fail at the first step? .. also you have a 5 at the end of the convergence test command .. which tells the analysis to go on even if convergence has not been reached (hence the warning message) .. sometimes that works, in your case, given the next norm, obviously not.