Analysis of fractured rock and gas flow interaction in explosion simulations

In this study, an attempt has been made to adopt a combined finite discrete element methodology to couple gas dynamics equations and solid deformation states to develop a numerical tool for simulation of blast damage in brittle solid media such as rocks. A standard finite-element method is used, accompanied by strain softening behavior for modeling initiation and propagation of solid cracks due to high gas pressures. This variable high pressure is governed by the gas mass and momentum conservation equations. The gas behavior is fully coupled by the solid deformation which changes the density and porosity required in the gas dynamics equations and is based on new modifications to the recently proposed approach by the same authors. The proposed model for the flow of the detonation gas allows for evaluation of the spatial distribution of pressure and mass of the detonation gas over a complex geometry of cracked/fragmented solid (rock) model. Full geometric and material nonlinearities are taken into account by using a fully deformable finite-element mesh and cracked/fragmented discrete elements. Local adaptive remeshing (enrichment) techniques are used to geometrically simulate the crack propagation.