Large transverse deformation of double-layered rectangular plates subjected to gas mixture detonation load

Abstract

A series of twenty experimental tests were first carried out to assess the large transverse deformation of double-layered rectangular plates subjected to gas mixture detonation load. Specimens were made from a combination of an aluminum alloy front layer (the impulse-receiving face) and a mild steel back layer. Four different types of thickness configurations, namely, 1 mm + 1 mm, 2 mm + 1 mm, 1 mm + 2 mm, and 2 mm + 2 mm were selected to bring an insight into the influence of back and front layer thicknesses on the deformation resistance of double-layered plates. Each specimen group was subjected to five different pre-detonation pressures of acetylene and oxygen mixture. Quantitative experimental results were obtained and discussed in detail. The experimental results showed that the back layer deflection was approximately equal to the front layer deflection when there was no gap between the layers and the front layer had a lower strength and density than the back layer. A closed-form analytical model based on energy method was developed for double-layered plates subjected to the uniform impulsive loading. Furthermore, empirical design formulae were derived based on new dimensionless numbers to predict the maximum permanent deflection of back and front layers. The influence of strain rate sensitivity of materials was considered in both analytical and empirical models. An encouraging agreement between the experimental, analytical and empirical results in terms of the normalized deflection was achieved.