Error in PushOver analysis of concentrated plasticity model

[omidgahremani]

my model is constructed of elastic elements with localized plastisity at both end using zerolength elements."
I am running opensses on my steel structure to perform a pushover analysis but the analysis fails and none of my recorders works correctly and I have no output after running the model.
when I use Transformation constraints this warning appears :
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Modified Ibarra-Medina-Krawinkler Model with Bilinear Hysteretic Response
WARNING: CTestNormDispIncr::test() - failed to converge
after: 3000 iterations
ModifiedNewton::solveCurrentStep() -the ConvergenceTest object failed in test()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 87 with domain at load factor -0.0379817
OpenSees > analyze failed, returned: -3 error flag
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and when I use the Plain constraint the below massage appears :
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Modified Ibarra-Medina-Krawinkler Model with Bilinear Hysteretic Response
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 221
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 221
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 231
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 231
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 241
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 241
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 321
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 321
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 331
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 331
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 341
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 341
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 421
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 421
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 431
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 431
WARNING PlainHandler::handle() - constraint at dof 0 already specified for constrained node in MP_Constraint at node 441
WARNING PlainHandler::handle() - constraint at dof 1 already specified for constrained node in MP_Constraint at node 441
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the analysis features of my model is :

"constraints Transformation
numberer PLain
system BandGeneral
test NormDispIncr 1.e-6 3000
algorithm ModifiedNewton
integrator DisplacementControl 441 1 0.001
analysis Static
analyze 500"
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I'm looking forward to your kind helps and instructions.
best gratitudes .

[skamalzare]

Omid,

Your analysis with Transformation constraints is just not converging. Either, you have not define your model right or your convergence is too tight. You might want to change the way you apply the load/displacement too (e.g. go for smaller displacements).

Plain and Transformation constraints are sometimes very sensitive. If you look at the Wiki, you can see that, they cause problem when you assign different boundary conditions to one node. I think that's the error you are receiving for plain constraints. The best way to handle this can be by using Penalty constraints.

There is nothing wrong with your recorders, your analysis must finish and wipe for the recorders to save the results. Your analysis did not finish, therefore it never saved the results.

Bests,
Soheil

[omidgahremani]

Thank you so much.

[LiuHHuanhuan]

hi，omid. I had the same problem.I tried the approach suggested by ska, but my problem was not solved.I hope to get your help.thanks

[selimgunay]

How many DOF are you modeling with the zerolength element, is it only rotation? If that is the case, you need to use equaldof for other DOF or a rigid material to model those DOF.