*DRUCKER PRAGER HARDENING

Optional parameters

DEPENDENCIES

Set this parameter equal to the number of field variable dependencies included in the definition of the yield stress, in addition to temperature. If this parameter is omitted, the yield stress depends only on the plastic strain and, possibly, on temperature. See “Using the DEPENDENCIES parameter to define field variable dependence” in Material Data Definition for more information.

RATE

Set this parameter equal to the equivalent plastic strain rate, ${\dot{\overline{\epsilon }}}^{pl}$, for which this hardening curve applies. This parameter should be omitted if the RATE DEPENDENT option or the DRUCKER PRAGER CREEP option is used. Rate-independent behavior is assumed if the RATE parameter, the RATE DEPENDENT option, and the DRUCKER PRAGER CREEP option are not used.

TYPE

Set TYPE=COMPRESSION (default) to define the hardening behavior by giving the uniaxial compression yield stress, ${\sigma }_c$, as a function of uniaxial compression plastic strain, ${\overline{\epsilon }}^{pl}=\left|{\epsilon }_{11}^{pl}\right|$.

Set TYPE=TENSION to define the hardening behavior by giving the uniaxial tension yield stress, ${\sigma }_t$, as a function of uniaxial tension plastic strain, ${\overline{\epsilon }}^{pl}={\epsilon }_{11}^{pl}$.

Set TYPE=SHEAR to define the hardening behavior by giving the cohesion, $d=\frac{\sqrt{3}}{2}\tau \left(1+\frac{1}{K}\right)$, as a function of equivalent shear plastic strain, ${\overline{\epsilon }}^{pl}={\gamma }^{pl}/\sqrt{3}$, where $\tau$ is the yield stress in shear, K is the ratio of flow stress in triaxial tension to the flow stress in triaxial compression, and ${\gamma }^{pl}$ is the engineering shear plastic strain.