Non-uniform isentropic gas flow analysis of explosion in fractured solid media

This paper presents a new formulation of non-uniform isentropic gas flow during an explosion in solid media. The present form takes into account additional effects of variations in geometries of voids and crack openings. Variations of mass, density, pressure and internal energy of the gas are analyzed throughout the explosion process, as a means of assessing the feasibility of the adopted approach and verifying the results. The solid material is modeled by a combined finite/discrete element method which is capable of modeling progressive cracking and fragmentation and any potential normal and frictional contacts during the cracking and post-cracking phases. Re-meshing is performed to geometrically model creation/propagation of new cracks or fragments. The proposed algorithm combines the simplicity of the gas flow formulation with the generality of the combined finite/discrete element to achieve a coupled solution for interaction of gas flow and fractured solid in an explosion process. A set of simple classical tests and complex progressive fracturing of a solid domain due to explosion are simulated to assess the overall performance of the proposed approach.