How can we improve behavior of nonlinear beam column?

Forum for OpenSees users to post questions, comments, etc. on the use of the OpenSees interpreter, OpenSees.exe

Moderators: silvia, selimgunay, Moderators

Post Reply
semon
Posts: 39
Joined: Fri Jul 27, 2012 2:53 pm

How can we improve behavior of nonlinear beam column?

Post by semon »

Hi Everyone,

I am working on a bridge model with contact element to simulate the abutment and deck interaction. The model runs well without contact element and shows some errors while running the model with contact element. The model cannot converge with the contact element, I think it is due to non-convergence of nonlinear beam column element. How can I improve the behavior of the nonlinear beam column?

The error that shows up while running the model is as follows:

WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 52(dW: << 0.00542727, dW0: 27.7979)
Domain::update - domain failed in update
Newmark::update() - failed to update the domain
WARNING NewtonRaphson::solveCurrentStep() -the Integrator failed in update()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 7.38
OpenSees > analyze failed, returned: -3 error flag
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 52(dW: << 0.00542727, dW0: 27.7979)
Domain::update - domain failed in update
Newmark::update() - failed to update the domain
WARNING NewtonRaphson::solveCurrentStep() -the Integrator failed in update()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 7.38
OpenSees > analyze failed, returned: -3 error flag
CTestNormDispIncr::test() - iteration: 1 current Norm: 0.629986 (max: 0.1, Norm deltaR: 134162)
CTestNormDispIncr::test() - iteration: 2 current Norm: 0.000515823 (max: 0.1, Norm deltaR: 134152)

-------------------------Bar failed---------------------------
-------------------------Bar failed---------------------------
-------------------------Bar failed---------------------------
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 53(dW: << 0.000689981, dW0: 44.3896)
Domain::update - domain failed in update
Newmark::update() - failed to update the domain

Thank you,
Semon
gerber
Posts: 35
Joined: Thu Apr 12, 2012 10:09 am
Location: National Technical University of Athens

Re: How can we improve behavior of nonlinear beam column?

Post by gerber »

Try to change the iteration of the nlbeam-column element . The default value is 10^-16 , its too high !!!
semon
Posts: 39
Joined: Fri Jul 27, 2012 2:53 pm

Re: How can we improve behavior of nonlinear beam column?

Post by semon »

Hi
Hi all,

I decreased and increased the default test tolerance of the element, 52, which failed to converge and it did make any difference in the model. It shows same kind of error in same time. Do I have to change the tolerance in every elements.

The strange part is that the model runs perfectly for other three inputs except the fourth one and all three earthquake loading have 25 inch of maximum displacement.

Thanks
Post Reply