Elasto-plastic analysis of masonry with anisotropic plastic material model

This paper establishes an anisotropic plastic material model to analyze the elasto-plastic behavior of masonry in plane stress state. Being an anisotropic material, masonry has different constitutive relation and fracture energies along each orthotropic axes. Considering the unique material properties of masonry, a new yield criterion for masonry is proposed combining the Hill's yield criterion and the Rankine's yield criterion. The new yield criterion not only introduces compression friction coefficient of shear but also considers yield functions for independent stress state along two material axes of tension. To solve the involved nonlinear equations in numerical analysis, several nonlinear methods are implemented, including Newton-Raphson method for nonlinear equations and Implicit Euler backward mapping algorithm to update stresses. To verify the proposed material model of masonry, a series of tests are operated. The simulation results show that the new developed material model implements successfully. Compared with isotropic material model, the proposed model performs better in elasto-plastic analysis of masonry in plane stress state. The proposed anisotropic model is capable of simulating elasto-plastic behavior of masonry and can be used in related applications.