Why do I get this error with ViscousDamper material

[rmandok]

I want to model viscous damper and according to OpenSees wiki i use this material
uniaxialMaterial ViscousDamper $matTag $K $Cd $alpha
but when I attempted to run my code, I got this warning:

WARNING could not create uniaxialMaterial ViscousDamper

while executing
"uniaxialMaterial ViscousDamper $Viscous $K $Cd $alpha "
(file "OpenSees/Modelling.tcl" line 16)
invoked from within
"source OpenSees/Modelling.tcl"
(file "GoAll.tcl" line 14)

Please help me!
(note: I am using OpenSees 2.4.0)
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And when I download OpenSees 2.4.1
I've got this error:
(note: I use nonlinearBeamColumn for viscous damper and it is spreading out from node 1 (left column bottom) to node 4 (right column top) and my frame is a 1story 1bay moment frame and the code runs quite well without the damper)

ViscousDamper Model by S. Akcelyan and D.G. Lignos, McGill University
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.#QNAN)
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.06221e-012)
Domain::update - domain failed in update
LoadControl::update - model failed to update for new dU
WARNING NewtonRaphson::solveCurrentStep() -the Integrator failed in update()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at load factor 0.1
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.#QNAN)
Domain::update - domain failed in update
OpenSees > analyze failed, returned: -3 error flag
groundmotion start!.Time: 0.000000
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.00108e-012)
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 0.005
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.#QNAN)
Domain::update - domain failed in update
OpenSees > analyze failed, returned: -3 error flag

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So after getting this error I changed element from nonlinearBeamColumn to zeroLength but this time I've got this error:

ViscousDamper Model by S. Akcelyan and D.G. Lignos, McGill University
WARNING ZeroLength::setDomain(): Element 5 has L= 3.5, which is greater than the tolerance
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 1(dW: << -1.#IND)
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 2(dW: << 1.#QNAN)
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 3(dW: << 1.#QNAN)
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 4(dW: << -1.#IND)
Domain::update - domain failed in update
LoadControl::update - model failed to update for new dU
WARNING NewtonRaphson::solveCurrentStep() -the Integrator failed in update()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at load factor 0.1
OpenSees > analyze failed, returned: -3 error flag

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ans here is my analysis code:


constraints Plain
numberer RCM
system SparseGeneral -piv
test NormDispIncr 1.0e-8 10
algorithm Newton
integrator Newmark 0.5 0.25
analysis Transient
analyze [expr int($tGM/$dtAn)] $dtAn



I must mention this again that without viscous damper everything is just fine and the code works properly.
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Here is where you can download my code:
http://snk.to/f-chp8v58p

[vesna]

Are you using the latest version of OpenSees? This is a new material so you need to use the latest version of OpenSees for it to work.

[rmandok]

Dear Vesna,
As I mentioned above I download the latest version and try again and still i get this error

ViscousDamper Model by S. Akcelyan and D.G. Lignos, McGill University
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.#QNAN)
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.06221e-012)
Domain::update - domain failed in update
LoadControl::update - model failed to update for new dU
WARNING NewtonRaphson::solveCurrentStep() -the Integrator failed in update()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at load factor 0.1
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.#QNAN)
Domain::update - domain failed in update
OpenSees > analyze failed, returned: -3 error flag
groundmotion start!.Time: 0.000000
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.00108e-012)
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 0.005
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 5(dW: << 1.#QNAN)
Domain::update - domain failed in update
OpenSees > analyze failed, returned: -3 error flag

and here is my modelling code:
http://snk.to/f-chp8v58p

It seems, right after defining nonlinearBeamColumn element for viscous damper, I get the first warning.

I even change the element to truss element and corotruss elementbut it didn't work!

[vesna]

Try to contact the developer of the material.