Numerical Simulation of Free-Air Explosion Using LS-DYNA

Abstract

The development of advanced computational technologies in recent years has seen studies of the effects of explosions on large structures becoming feasible and, as a consequence, the number of destructive tests and their high cost can be reduced significantly. This paper presents a study of air-burst explosion wave propagation using computational modelling based on LS-DYNA. Incident and reflected pressure waves are investigated, as well as the mesh sensitivity, different scaled distances and the charge shape. The Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE) representation is used to model the blast, and the results are validated by empirical methods. The effects of parameter values adopted in these methods are studied. The results show that LS-DYNA can effectively simulate an air-burst explosion. Additionally, the mesh size and explosive weight have a large influence on the peak incident and reflected pressures. It is observed that there is an optimum range of the mesh size in relation to the explosive weight, material properties and the scaled distance which can significantly reduce the CPU usage while having reasonable accuracy. Different charge shapes cause different pressure distributions over the air domain.