problem with elastomeric bearing

[Maur0]

Hi,
I modeled an 2D inelastic column in this way:
node1=bottom of column (fix)
node2=top of column
node3=node where I apply a mass
a nonlinearBeamColumn element connect nodes 1 2.
At a first time I created a rigidLink beam 2 3 and I run static analysis (done successfully).
At a second time I created a elastomericBearingPlasticity element defined in this way:
set klat 1577.;
set fyiso 200000.;
set alpha1 1.;
set alpha2 0.;
set mu 0.;
set IDmatisoP 4 ;
set IDmatisoMz 5 ;
uniaxialMaterial Elastic $IDmatisoP 100000000. ;
uniaxialMaterial Elastic $IDmatisoMz 100000000. ;
element elastomericBearingPlasticity 2 2 3 $klat $fyiso $alpha1 $alpha2 $mu -P $IDmatisoP -Mz $IDmatisoMz;
(unit: N, mm, ton).
I run analysis (analysis object are these:
set Tol 1.0e-8;
constraints Transformation;
numberer RCM;
system BandGeneral;
test NormDispIncr $Tol 6 ;
algorithm Newton;
set NstepGravity 10;
set DGravity [expr 1./$NstepGravity];
integrator LoadControl $DGravity;
analysis Static;
analyze $NstepGravity;)
but I have these message:
WARNING BandGenLinLapackSolver::solve<> -LAPACK routine returned 1
WARNING NewtonRaphson::solveCurrentStep<> -the LinearSysOfEqn failed in solve<>
StaticAnalysis::analyze<> -the Algorithm failed at iteration: 0 with domain at load factor 0.1
OpenSees> analyze failed, returned: -3 error flag

What do I have to do to overcome this problem?
Thanks

[maksins]

It might be related to ill-conditioned matrix due to very high values of stiffness you are providing in axial and moment direction. Usually, an elastomeric bearing would have vertical stiffness that 100-500 times the horizontal stiffness. So use 500000 for vertical stiffness (you can actually determine this!). Why are using such a high value for Mz? Elastomeric bearings are not rigid in moment or torsion, on the contrary, they are flexible. Use any realistic value like 1000, it is not going to affect your response in shear and axial direction substantially. Try to run your model with these representative values, and see if it's because of this problem.