Numerical study of blast mitigation effect of innovative barriers using woven wire mesh

Abstract

Protective barriers are regarded as a useful means to enhance the safety level of buildings and residents in cases of air blast and impact scenarios. However, only limited research exists concerning the properties and effectiveness in mitigating the blast loads of air-permeable metallic barriers, which requires far fewer materials than ordinary solid walls. This paper explores the blast mitigation effect of an innovative barrier type using woven wire mesh. Numerical models were developed and validated against the experimental values of both peak overpressures and maximum impulses, which were published by the authors in a previous study. The influence of the Mach stem formation, which is attributed to the small elevation of the explosive charge above the ground surface, on the blast loads is also examined. It is found that the Mach stem formation significantly affects the peak overpressure at gauge ps1 (1 m ahead of the barriers), whereas its effects on the peak overpressures at the remaining gauges and on the maximum impulses at all gauges are negligibly small. This indicates that the validated numerical models can be used to assess the blast mitigation effect behind the barriers. Based on the numerical results at the employed gauges, the barriers using woven wire mesh can achieve an overpressure (impulse) reduction as high as 31.6% (41.6%) with respect to the free field scenario, in which no obstacles exist in the path of the shock wave propagation. Furthermore, the validated numerical models are used to shed light on the barrier behaviour against air blast by analysing the overpressure-time histories and by visualizing the shock wave propagation. This assists in pointing out the underlying reasons for the noticeable phenomena observed in the experiments. Moreover, two parametric studies are conducted in order to discuss the impact of the gabion wall thickness and the opening span between the gabion walls on the blast mitigation effect of barriers.