Dynamic shear band evolution by the numerical manifold method and the Drucker Prager model

Abstract

To simulate the dynamic evolution of shear band in soil, the numerical manifold method (NMM) and the Drucker Prager model (DP) are used. Considering that the soil does not bear tension, the tensile part of DP is cut off. Then the constitutive integration could be reduced to mix complementarity problem, which is solved by the Gauss Seidel projection contraction method (GSPC). The discretization sequence is altered to resolve the transfer issue of degrees of freedom when dealing with dynamic discontinuities evolving. Different with the traditional discretization approach, the discretization of temporal variable is set prior to that of spatial variable so that all the degrees of freedom are valid only in a current step without the necessity to be transferred to the next time step. In this way, the shear band tip could stop anywhere naturally, without being improperly forced to stay on the element edge. For simplicity, the shear band is treated as a strong discontinuity with zero width. The interface contact is described by the NMM contact approach where open-close iteration is involved. Finally, a soil dam is studied to check the capability of the proposed method to capture the dynamic evolution of shear band.