Drucker-Prager UMAT代码

代码说明：

ABAQUS UMAT; Drucker-Prager; 随动硬化The development of a pressure-dependent constitutive model with combined multilinear kinematic and isotropic hardening is presented. The constitutive model is developed using the ABAQUS user material subroutine (UMAT). First the pressure-dependent plasticity model is derived. Following this, the combined bilinear and combined multilinear hardening equations are developed for von Mises plasticity theory. The hardening rule equations are then modified to include pressure dependency. The method for  implementingthe new constitutive model into ABAQUS is given. Finally, verification