Dynamic analysis of cylindrical shells subject to multiple blasts using FSI

Abstract

Localised pressure pulse loads can pose a significant threat to structural elements as well as critical equipment and may cause failure and damage in the target due to the concentrated energy delivered upon a localised area of the target. The impulse impinged upon the localised zone at the contact interface can exceed 80% of the total impulse that the charge can deliver to the infinite target, leading to potential perforation of the structural element. When multiple charges are detonated, the advection of gaseous products depends, among other parameters such as fluid density, mass, and shape, on the type of blast wave interference and superposition. This work examines the influence of multiple charge detonations blasted in the air on the external surface of cylindrical shells. Two types of detonations were considered, viz. simultaneous and sequential. In both cases the charges were positioned at 50mm and 75mm stand-off to the right and left of the shell. The Fluid-Structure Interaction (FSI) phenomenon was investigated in each scenario. The pressure registered with the gauge points of the rigid target was implemented in an uncoupled study on a flexible target which demonstrated different mode shapes occurring in the shell due to each blast scenario. A dimensionless impulse parameter was defined based on the Gaussian distribution function associated with the load shape, which renders the probability of the impulse as the total impulse that can potentially be imparted to the target.