Debris characteristics and scattering pattern analysis of reinforced concrete slabs subjected to internal blast loads-a numerical study

High velocity debris is a major threat to the safety of the surrounding area during an explosion accident. Since reinforced concrete (RC) is the most universal civil and military building material, it is of great significance to study the characteristics and launching trajectory of debris following a blast load. In this study, based on the LS-DYNA software, the dynamic failure process of an RC slab under an internal blast load is first investigated using the Arbitrary Lagrangian-Eulerian (ALE) method and the multi-material fluid-solid coupling method. For fulfilment, a zero-thickness cohesive element is introduced to simulate the concrete failure under a blast load in order to avoid the mass loss caused by a conventional element erosion algorithm. Then, since it is very time-consuming to conduct an LS-DYNA simulation through to the end, which is when all the debris has landed on the ground, a faster scheme is proposed in tandem with the LS-DYNA numerical analysis to predict the flight path and scattering pattern of the debris produced. Finally, the size distribution, launching angle, launching velocity and projectile distance of the debris following the breakup of the RC slab under different internal blast loads are analysed.