Analysis of shear band bifurcation with a hypoplastic model for a pressure and density sensitive granular material

The focus of the present paper is to investigate the possibility of shear band bifurcation in rate-independent, cohesionless and dry granular materials based on a hypoplastic constitutive model. The hypoplastic constitutive model is of the rate type and incrementally nonlinear. The current density is included in the constitutive model as a state parameter in addition to the stress tensor. With a unified description of the interaction between pressure level and limit densities the model can be applied to a wider range of pressures and densities. Thus, the influence of density and pressure on the initiation of shear bands can be investigated with the a single set of constitutive constants. For plane strain compressions starting from various initial densities and pressures the predictions of the bifurcation analysis are discussed and compared with earlier investigations.