The Influence of Boundary Condition on Numerical Simulation of Blast Shock Wave by LS-DYNA

Abstract

The propagation of TNT blast wave in the air is simulated by using the LS-DYNA finite element analysis software, to study the influence of boundary condition on the overpressure of blast shock wave. In the simulation, three kinds of blast equivalent are selected, which are 5.12 kg, 51.2 kg and 512kg. Angles between four groups of measuring points which are selected and positive X axis are 0°, 30°, 45°, 60° respectively. In addition, two boundary conditions are selected in the simulation, the zero displacement constraint boundary and the non-reflective boundary. The results indicate that simulation results have better stability when the scaled-distance Z>1.2. Secondly, different boundary conditions have different influences on shock wave overpressure, and non-reflective boundary condition will reduce the overpressure value in the vicinity of the boundary. What's more, reasonable selection of measuring points should be emphasized. For example, to select the measurement point of 45 °angle with positive X axis to obtain the overpressure value is more accurate for a 1/4 cylinder model.