Is there any example for Mohr-Coulomb yield criterion based perfect plasticity simulations

[Yulongggggg]

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Question

<recently I am using 'SolidMechanicsPlasticMohrCoulomb' and 'ComputeMultiPlasticityStress' to simulate the perfect plasticity simulation of tunneling process, but my numerical solution does not fit with the analytical solutions, so I was wonder if there's any example for this problem or I have misused the MOOSE objects? I have attached my code link below>

[Yulongggggg]

https://github.com/Yulongggggg/Plasticity

[GiudGiud]

You used this
material_output_family = 'MONOMIAL'
material_output_order = 'FIRST'
but the exodus output of first order monomial is not great (it's a difficult problem). Try constant monomials

could you try with this object instead of computeMultiplePlasticity?
https://mooseframework.inl.gov/source/materials/IsotropicPlasticityStressUpdate.html

[Yulongggggg]

Thank you! I was thinking if the constant monomials will decrease my computational accuracy. Because i have used constant monomials before and the precision is not promising. I see that the yield criterion used in [IsotropicPlasticityStressUpdate is von mises, and I am simulating the rock behavior so i'd better use the mohr-coulomb

[GiudGiud]

If it's just for output purposes then it does not matter what the precision is?

If you are using the material property output for the calculation we ll have to be a little careful

[Yulongggggg]

Thank you for helping, yeah, I might use it for further calculation. I have another question: since the mohr-coulomb yield criterion hasn't been documented yet, I was wondering what plastic potential function is used in the mohr-coulomb plasticity calculation, is it identical to the yield function or have different form?

[GiudGiud]

You are talking about the user objects for Mohr Coulomb?
@WilkAndy

[Yulongggggg]

I mean, since the Mohr-coulomb in MOOSE is non-associate, can you give me the form of plastic potential involved in the plastic calculation of MOOSE