Mohr-Coulomb

The Mohr-Coulomb plasticity model:

• is used to model materials with the classical Mohr-Coloumb yield criterion;
• allows the material to harden and/or soften isotropically;
• uses a smooth flow potential that has a hyperbolic shape in the meridional stress plane and a piecewise elliptic shape in the deviatoric stress plane;
• is used with the linear elastic material model;
• can be used with the Rankine surface (tension cutoff) to limit load carrying capacity near the tensile region; and
• can be used for design applications in the geotechnical engineering area to simulate material response under essentially monotonic loading.

You can define flow potential eccentricities in both the meridional and deviatoric planes.

The meridional eccentricity, $ϵ$ , is a small positive number that defines the rate at which the flow potential approaches its asymptote.

Input Data	Description
Eccentricity	Meridional eccentricity, $ϵ$ .

The deviatoric eccentricity, $e$ allows the shape of flow potential in the deviatoric stress space to be controlled independently of the angle of friction. If this parameter is omitted, the deviatoric eccentricity is calculated by default as $e=(3-\sin \left(\varphi \right))/(3+\sin \left(\varphi \right))$ where $\varphi$ is the Mohr-Coulomb angle of friction defined on the data lines.

Input Data	Description
Deviatoric Eccentricity	Deviatoric eccentricity, $1/2<e\le 1$ .

The plasticity model requires you specify a friction angle, $\varphi$ , at high confining pressure in the $p-R_{mc}q$ plane and the dilation angle, $\psi$ , in the $p-R_{mw}q$ plane. $R_{mc}$ is a is a measure of the shape of the yield surface in the deviatoric plane and $R_{mw}$ controls the shape of the flow potential $G$ in the deviatoric plane.

Input Data	Description
Friction Angle	Friction angle, $\varphi$ . The friction angle can range from $0^{°}\le \varphi \le {89.9}^{°}$ .
Dilation Angle	Dilation angle, $\psi$ . The dilation angle can range from $0^{°}\le \psi \le {89.9}^{°}$ .
Use temperature-dependent data	Specifies material parameters that depend on temperature. A Temperature field appears in the data table. For more information, see Specifying Material Data as a Function of Temperature and Independent Field Variables.
Number of field variables	Specifies material parameters that depend on one or more independent field variables. A Field column appears in the data table. For more information, see Specifying Material Data as a Function of Temperature and Independent Field Variables.