Reply To: Soil container modeling – Mohr Coulomb (Material)

[peteroznewman]

Dear Maria Fernanda,

Try setting up Automatic Time Stepping and using an Initial and Minimum Substep to be 1000. That might help it converge for at least a few substeps.

I have a little experience with the Mohr-Coulomb material model. One way to gain experience with the material model is with a unit cube. Use Frictionless support on three sides of the cube that share one corner. On one opposite face, apply a Displacement load such as a small amount of compression or a small amount of tension. Mesh the cube with 1 linear element so there are only 8 nodes. See what happens.

In the model of the stacked rubber sheets that has rectangular sheet on the bottom representing soil, change the material from soil to a linear elastic isotropic material. Solve this and look at the stress on the sides of the “soil” block. That block has a Fixed Support on the bottom. How is it connected to the rubber sheet touching it?  Is it Bonded Contact?  Look at the side walls of that “soil” block. Are they bulging out with the weight of the rubber above it? Maybe the reason this model will not converge with a M-C soil material is because stress develops in the material which it cannot support.

What might work is to increase the soil block by 4 times its current dimensions in length, width and depth. Now the side walls are far from the rubber block. Apply a Fixed Support to the side wall of the soil block as well as the bottom face. Please let me know what you find out.

Regards,

Peter