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How to adjust yield surface of Drucker-prager in soil plasticity

Posted Jul 3, 2023, 9:33 p.m. EDT Geomechanics Version 6.0 2 Replies

Han Xinkai
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Dear All

I am an absolute beginner at COMSOL Multiphysics and I am trying to add soil plasticity in this model, I use Drucker-Prager failure criteria, but many problem existed in this model. I can not use this model for time dependent modeling, because the software always report me mistake: Failed to find consistent initial values, Failed to compute elastoplastic strain variables, last time step is not converged.

Thank you in advance.

2 Replies Last Post Jul 5, 2023, 2:46 a.m. EDT
Henrik Sönnerlind COMSOL Employee

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Posted: 1 year ago Jul 4, 2023, 2:57 a.m. EDT

Probable reason: You apply too much load at t=0, or have inconsistent boundary conditions so that no converged solution can be found. Try to apply the loads more gradually.

If it is a problem of finding an initial state for a dynamic analysis, you can use a stationary study step to get appropriate initial conditions.

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Henrik Sönnerlind
COMSOL
Probable reason: You apply too much load at t=0, or have inconsistent boundary conditions so that no converged solution can be found. Try to apply the loads more gradually. If it is a problem of finding an initial state for a dynamic analysis, you can use a stationary study step to get appropriate initial conditions.
Han Xinkai
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Posted: 1 year ago Jul 5, 2023, 2:46 a.m. EDT
Updated: 1 year ago Jul 5, 2023, 2:56 a.m. EDT

Probable reason: You apply too much load at t=0, or have inconsistent boundary conditions so that no converged solution can be found. Try to apply the loads more gradually.

If it is a problem of finding an initial state for a dynamic analysis, you can use a stationary study step to get appropriate initial conditions.

Dear Dr

abourt Knowledgebase entry 1150 discusses this error message.

www.comsol.com/support/knowledgebase/1150/

Do you know how to set "The elastoplastic element fails to evaluate the consistency conditions (due to either loads, displacements, initial stress/strains), and it fails to compute the first elastic-predictor step. That is, your initial state, e.g. assumed in-situ stresses in a geomechanical problem are outside the yield surface." in the first load step?

How can i change the equation view under soil plasticity or change initial stress & strain?

Thanks

>Probable reason: You apply too much load at t=0, or have inconsistent boundary conditions so that no converged solution can be found. Try to apply the loads more gradually. > >If it is a problem of finding an initial state for a dynamic analysis, you can use a stationary study step to get appropriate initial conditions. Dear Dr abourt Knowledgebase entry 1150 discusses this error message. www.comsol.com/support/knowledgebase/1150/ Do you know how to set "The elastoplastic element fails to evaluate the consistency conditions (due to either loads, displacements, initial stress/strains), and it fails to compute the first elastic-predictor step. That is, your initial state, e.g. assumed in-situ stresses in a geomechanical problem are outside the yield surface." in the first load step? How can i change the equation view under soil plasticity or change initial stress & strain? Thanks

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