Steady-state flow of compressible rigid–viscoplastic media

Computational methods for modeling steady-state flow of compressible rigid viscoplastic fluids are proposed. The constitutive equation used captures the combined effects of high-strain rate and high-pressure on the behavior of porous materials.A mixed finite-element and finite-volume strategy is developed. Specifically, the variational inequality for the velocity field is discretized using the finite element method and a finite volume method is adopted for the hyperbolic mass conservation equation. To solve the velocity problem a decomposition–coordination formulation coupled with the augmented lagrangian method is used. This approach is accurate in detecting the viscoplastic regions and permit us to handle the locking medium condition.The proposed numerical method is then applied to model the penetration of a rigid projectile into cementitious targets. The numerical model accurately describes the density changes around the projectile, the stress field, as well as the shape and location of the deformation zone (viscoplastic region) in the target.