Working with J2Plasticity material in OpenSees

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Working with J2Plasticity material in OpenSees

Post by maajidian » Thu Jun 04, 2020 10:33 pm

Dear friends,

I have some problems with modeling a simple short cantilever steel column (as a shear link element) as follow:
If I make a use of nD Material like J2plasticity and nD Fiber, the elastic stiffness is correct but the yield point is not reachable (3D model) and we have convergence or flexibility error.

WARNING: numeric analysis returns 1 -- Umfpackgenlinsolver::solve
WARNING AcceleratedNewton::solveCurrentStep() -the LinearSysOfEqn failed in solve()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at load factor 5
OpenSees > analyze failed, returned: -3 error flag

How can I work correctly with J2plsticity for modeling in OpenSees?
Can I model it in 2D form?

# Units are in Newton and meter
model basic -ndm 3 -ndf 6
node 1 0.0 0.0 0.0
node 2 0.0 0.3 0.0
fix 1 1 1 1 1 1 1
set Es 2.1e11; # modulus of elasticity for steel Pa
set Fy 2.4e8; #yield stress of steel N/m2
nDMaterial J2Plasticity $matID $K $G $Fy $Fyf $b 1
WSectionND $secTagLink $matID_K 0.27 0.28 0.013 0.008 8 1 1 2
geomTransf PDelta $transfTag 1 0 0
element nonlinearBeamColumn 8 1 2 5 $secTag $transfTag -iter $maxIter $tol

Best wishes

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