NonlinearPeric

Viscoplasticity

Similar to the classic rate independent J2 plasticity, the NonlinearPeric class defines a J2 plasticity incorporates viscoplatisicity using Peric's model, that is

$$\dot\gamma(\sigma,\sigma_y)=\left\{\begin{array}{ll}\dfrac{1}{\mu}\left[\dfrac{q(\sigma)}{\sigma_y}-1\right] ^{1/\epsilon},&\Phi\ge0,\\0,&\Phi<0.\end{array}\right.$$

In which, $\mu$ is viscosity related parameter, $\epsilon$ is rate sensitivity, larger $\epsilon$ represents response to be more sensitive to rate, $q(\sigma)=\sqrt{\dfrac{3}{2}\eta:\eta}$ as before is the effective von Mises stress.