Development of a lightweight mitigation system for severe explosions with small-scaled distances

The recent increase in the number of terrorism-related explosions requires extensive research efforts to minimize their significant socio-economic impacts. One key strategy is to protect vulnerable structures using mitigation systems to reduce the destructive effects of pressure waves associated with explosions. In this respect, the current study develops a Bilayer Lightweight Arched Steel (BLASt) system that can be used as a stand-alone mitigation system to protect either new or existing structures. Specifically, unlike conventional systems that use tough panels or interactions between different materials to confront blast waves, the developed system minimizes the effects of such waves by both controlling their paths through air gaps and splitting their directions through thin and curved steel plates. To demonstrate the mitigation performance of the system, the current study initially develops and validates a numerical model to simulate TNT charges as well as the blast response of reinforced concrete walls and steel panels that were presented in previous experimental studies. The model is then used to compare the response of the developed BLASt system to those of a reinforced concrete wall, a solid steel panel, and a corrugated steel panel—when all are subjected to explosion waves with similar small-scaled distances. The comparison results are presented in terms of the generated pressure and velocity of the particles behind the mitigation systems and their corresponding material strains, total deformations, and stresses. Finally, an interpretability analysis is performed using 62 possible configurations to investigate the effect of a wide range of design and geometrical parameters on the mitigation performance of the developed system. The results show that the pressure wave values behind the BLASt system were reduced by i) 66% and 62% compared to the solid and corrugated steel panels, respectively, each was of the same weight as the developed system; and ii) 77% compared to the free field. The interpretability analysis results also demonstrate that although the thickness of the back plates and the depth of the front and back plates are key protective factors, all the considered BLASt system configurations were able to achieve high mitigation levels compared to conventional steel systems. The current study will provide broad future research opportunities since the proposed system can be utilized as a blast mitigation fence for different structures and can be further extended to other applications (e.g., armoured vehicles) based on the required protection levels.