Experimental and numerical investigation on shock wave attenuation in a chamber.

New types of explosives, such as fuel-air explosive (FAE), are capable of generating high pressure and have a long duration of action, which is extremely destructive to personnel and equipment in underground spaces. Chambers are one of the most commonly used shock waves attenuating protection structures in engineering. However, the effect of the duration of shock wave action on the wave attenuation capacity of chambers with asymmetric structures has not been studied. This study investigates the wave attenuation characteristics of a chamber with double-bend structures under varying durations and pressures using a self-developed shock tube. Utilizing space-time conservation element and solution element (CESE), the effects of structural dimensions, duration, and the pressure of the incident shock wave on the attenuation ratio are analyzed. The results indicate that an increase in the duration of the incident shock wave causes a significant decrease in the wave attenuation ratio. When the duration extends from 0.13 s to 1.55 s, the attenuation ratio declines by 35%. The influences of incident shock wave pressure and chamber size on the attenuation ratio are contingent upon the chamber's capacity to accommodate shock waves and airflows. When the incident shock wave surpasses the shock wave accommodation capacity of the given chamber size, the attenuation ratio may drop sharply, potentially becoming negative, indicating that the chamber effectively amplifies the incident shock wave. This study aims to provide valuable guidance for the design of chamber-type wave attenuation structures in protective engineering applications.