Mohr Coulomb

{

    "materials": [
        {
            "id": 0,
            "type": "MohrCoulomb2D",
            "density": 2000,
            "youngs_modulus": 2e7,
            "poisson_ratio": 0.3,
            "friction": 25,
            "dilation": 0,
            "cohesion": 2000,
            "softening": true,
            "residual_friction": 13,
            "residual_dilation": 0,
            "residual_cohesion": 500,
            "peak_pdstrain": 0,
            "residual_pdstrain": 0.05,
            "tension_cutoff": 1000,
            "packing_fraction": 0.6,
            "packing_fraction_minimum": 0.4
        }
    ]

}

• "id" is the material ID corresponding to a subset (or all) of the generated material points.
• "type" is either "MohrCoulomb2D" or "MohrCoulomb3D".
• "density" is material density.
• "youngs_modulus" is the constant elastic parameter Young's modulus.
• "poisson_ratio" is the constant elastic parameter Poisson's ratio.
• "friction" is the friction angle (in degrees).
• "dilation" is the dilation angle (in degrees).
• "cohesion" is the cohesion.
• "softening" flag is set true for strain softening material.
• "residual_friction" is the friction angle (in degrees) at the end of softening.
• "residual_dilation" is the dilation angle (in degrees) at the end of softening.
• "residual_cohesion" is the cohesion at the end of softening.
• "peak_pdstrain" is the plastic deviatoric strain at the start of softening.
• "residual_pdstrain" is the plastic deviatoric strain at the end of softening.
• "tension_cutoff" is the tension cutoff strength.
• "packing_fraction" or "porosity" is the granular assembly's initial packing fraction or void fraction (or porosity).
• "packing_fraction_minimum" is the minimum packing fraction when the material can carry stress. Below this value, the material should not carry any stress. The default "packing_fraction_minimum" is 0.0, which reverts to standard Mohr-Coulomb.

Flow potential and other model details are provided in [1].

References

[1] Menetrey, Philippe, and K. J. Willam. "Triaxial failure criterion for concrete and its generalization." Structural Journal 92.3 (1995): 311-318.