Evaluating the blast mitigation performance of hard/soft composite structures through field explosion experiment and numerical analysis

The application of hard/soft composite structure in personnel armor for blast mitigation is relatively practical and effective in realistic protection engineering, such as the shell/liner system of the helmet. However, there is still lacking a reliable experimental methodology to effectively evaluate the blast mitigation performance when the structure directly contacts the protected target, which limits the development of protection structures. In this paper, we proposed a new method to evaluate experimentally and numerically the blast mitigation performance of hard/soft composite structures. The blast mitigation mechanism is analyzed. The hard/soft structures were composed of ultra-high molecular weight polyethylene (UHMWPE) composite and expanded polyethylene (EPE) foam. In field explosion experiment, a 7.0 kg trinitrotoluene (TNT) spherical charge is used to generate blast waves at a 3.8 m stand-off distance. A pressure test device is designed to support the tested structure and measure the transmitted blast pressure pulses after passing through the structure. Experimental results indicate that the hard/soft structures can mitigate the blast pressure pulse into the triangular pressure pulse, through making the pulse profile flatter, reducing the pressure amplitude, and delaying the pulse arrival time. Specifically, the combination of 7 mm UHMWPE composite and 20 mm EPE foam can reduce the blast pressure amplitude by 40%. Correspondingly, the finite element simulation is also carried out to understand the blast mitigation mechanism. The numerical results indicate that the regulation for blast pressure pulses mainly complete at the hard/soft interface, which is attributed to the reflection of pressure waves at the interface and the deformation of the soft layer compressed by the hard layer possessing kinetic energy. Furthermore, based on these analyses, the corresponding theoretical model is proposed, and it can well explain the experimental and numerical results. This study is meaningful for evaluating and designing high-performance blast mitigation structures.

Automated summary

This paper proposes a new method to experimentally and numerically evaluate the blast mitigation performance of hard/soft composite structures, and analyzes the blast mitigation mechanism of such structures. The experimental results show that the hard/soft structures can effectively mitigate the blast pressure pulse, and the numerical results and theoretical model support this finding. This study is meaningful for evaluating and designing high-performance blast mitigation structures.