ZeroLengthND element with ElasticIsotropic material

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triplerik
Posts: 3
Joined: Tue Apr 07, 2020 11:01 pm

ZeroLengthND element with ElasticIsotropic material

Post by triplerik » Tue Apr 07, 2020 11:16 pm

Dear user,

I am trying to incorporate the ElasticIsotropic material into a zerolengthND element.The reason i don't use uniaxial materials is because I want to create a single material in a single element that behaves based on input forces in all DOF. I can not find any examples nor information on this forum about the zeroLengthND element. When running the basic script below it gives the error ElasticIsotropicMaterial::getCopy -- subclass responsibility. Does anyone know how to solve this? is the material not intended for zerolengthND element, and if so, which material is? Many thanks in advance.


Edit:
I dived in the source code and it appears the element requires a meterial of type "planestrain", "planestress", "Threedimensional", "Platefiber" or "axisymmetric". I need the threedimensional type, but how is this defined by the user? It is nowhere to be found in the documentation and in the source code the header file "CThreeDimensional.h" is missing.

If someone could clarify this issue it would be greatly appreciated

The script:


wipe all;
model BasicBuilder -ndm 3 -ndf 6;

node 1 0.0 0.0 0.0 -mass 1 1 1 1 1 1
node 2 144.0 0.0 0.0 -mass 1 1 1 1 1 1
node 3 168.0 0.0 0.0 -mass 1 1 1 1 1 1
node 4 72.0 96.0 0.0 -mass 1 1 1 1 1 1

node 5 0.0 0.0 0.0 -mass 1 1 1 1 1 1


# Set the boundary conditions - command: fix nodeID xResrnt? yRestrnt?
fix 5 1 1 1 1 1 1
fix 2 1 1 1 1 1 1
fix 3 1 1 1 1 1 1

uniaxialMaterial Elastic 1 3000
nDMaterial ElasticIsotropic 2 3000 0.3 2000
geomTransf Linear 99 0. 0. 1.
element ElasticTimoshenkoBeam 1 1 4 3000 6000 10 1000 1000 1000 30 30 99
element ElasticTimoshenkoBeam 2 2 4 3000 6000 10 1000 1000 1000 30 30 99
element ElasticTimoshenkoBeam 3 3 4 3000 6000 10 1000 1000 1000 30 30 99
element zeroLengthND 4 1 5 2

pattern Plain 1 Linear {
# apply the load - command: load nodeID xForce yForce
load 4 100 -50 0 0 0 0
}

system BandSPD
constraints Plain
integrator LoadControl 1.0 10 1.0 1.0
algorithm Linear
numberer RCM
analysis Static

recorder Node -file ND1.out -load -nodes 4 -dof 1 2 3 4 disp

analyze 1
print node 4
print ele

exit

triplerik
Posts: 3
Joined: Tue Apr 07, 2020 11:01 pm

Re: ZeroLengthND element with ElasticIsotropic material

Post by triplerik » Mon May 11, 2020 8:17 am

Update:
The material "ElasticIsotropic3D" should be used. This material is not mentioned in the manual. Additionally, the ZeroLengthND element is not able to provide rotational stiffness. In this link you can find how to fix this, you need to be able to compile the OpenSees source code however (although this might change in the future). https://github.com/OpenSees/OpenSees/issues/310

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