Study on Shock‐Induced Chemical Energy Release Behavior of Al/W/PTFE Reactive Material with Mechanical‐Thermal‐Chemical Coupling SPH Approach

Abstract

Abstract Reactive materials (RMs) are usually prepared from metal/non‐metal mixed powders through hot processing. RMs are widely used in warheads since they are inert under common conditions but release massive amounts of energy in chemical reactions induced by impact loading. However, the shock‐induced chemical energy release during impact has a complicated mechanism and needs to be further explored. This work investigated the shock‐induced chemical energy release behavior of the Al/W/PTFE RM. The experimental results show that the energy release efficiency of RM in direct ballistic tests increases with increasing impact velocity ( v ), and the extent of chemical reaction ( y ) can reach ∼0.8 at v =1250 m s −1 . Meanwhile, we propose a new numerical simulation approach based on the LS‐DYNA software, combining the user‐defined equation of state considering the chemical reactions and the smoothed particle hydrodynamics (SPH) method. This approach can describe the ultra‐fast chemical reaction and crushing behavior of Al/W/PTFE RM during the impact process, taking into account the mechanical‐thermal‐chemical coupling effect. The relative errors of y between the numerical simulations and the experiments are below 25 %. Moreover, the simulation results also provide many details about the ultra‐fast chemical reactions. As v increases, the values of y and the maximum chemical reaction rate (d y /d t max ) also increase from 0.134 and 0.017 μs −1 at v =700 m s −1 to 0.882 and 0.181 μs −1 at v =1300 m s −1 , respectively.