New Stabilized Finite Element Method Embedded with a Cap Model for the Analysis of Granular Materials

Standard displacement-based finite element formulations show a tendency to lock in the modeling of nearly incompressible materials. This overly stiff response often leads to an overestimation of the collapse load for the system. In this paper we present a stabilized mixed displacement-pressure finite element method that can effectively model the nearly incompressible materials in their elastic and inelastic range. The stabilized formulation is free of volumetric locking effects and allows equal low-order interpolation for both the displacement and the pressure fields. The formulation is integrated with a three-surface elastoplastic cap model for the simulation and analysis of granular materials. The good performance of the method is demonstrated via numerical examples of the hydrostatic compression test for concrete and the bearing capacity and limit load analyses of flexible footings.