A two-mesh coupled gas flow–solid interaction model for 2D blast analysis in fractured media

Abstract

A 2D coupled two-mesh interaction model for blast gas flow through fractured and fragmented solid media is presented. It is mainly designed to solve blast problems where a complicated set of wide difficult phenomena are involved: shock waves, progressive fracturing, gas–solid interactions, stability of dynamic solution, contact mechanics, etc. The present approach is based on a gas flow through an equivalent porous medium and allows for temporal and spatial variations of mass, density, pressure and internal energy of the gas throughout the explosion process. The solid domain is represented by a combined finite/discrete element technique which is capable of modeling progressive cracking and fragmentation and any potential normal and frictional contacts during the cracking and post cracking phases. The approach allows for accurate evaluation of variations of geometries of voids and crack openings in order to facilitate the coupling effects on gas flow computations. A set of simple benchmark tests are used to verify the coupling and gas flow algorithms, while a rather complex engineering problem of progressive fracture of a masonry box due to an internal explosion is simulated to assess the overall performance of the proposed approach and to discuss various aspects of gas and solid phases in detail.