Predicting explosion and blast effects: A multi-scale experimental approach

critical infrastructures protection evaluation when exposed to terroristic or accidental blast wave propagation represents a core topic of research for the French public institute IrSN and the French-german military research institute ISl. The Institute for radiological Protection and Nuclear Safety (IrSN) and the French-german research Institute of Saint louis (ISl) actively cooperate on the evaluation of pressure effects generated by blast wave propagating in hemispherical geometry. During the past few years, IrSN developed a significant experience on hemispherical blast effect assessment using 42g reference hexomax® charges detonated in contact to a planar surface equipped with different types of pressure sensors (piezo-electric and piezo-resistive). based on this experience, ISl developed an outdoor blast-pad located at its own explosive range: 400g TNT equivalent charges are detonated in a factor 2 up-scaled version of IrSN test configuration. Similar sensors are flush-mounted inside a metallic rail integrated below the concrete pad surface. The objective of this joint work is to improve the knowledge on scaling laws for small plastic explosive charges (Semtex, c4 and hexomax®) and their corresponding TNT equivalencies. To achieve this goal, TNT charges were produced at ISl in order to provide a direct, realistic and reproducible reference at the corresponding scale. In addition, the influence of the pressure gauge technology on the blast characteristics was studied and a methodology was developed to minimize this influence and provide guidelines for results comparison between research institutes. Finally, the pressure profiles were also analysed taking into account the fine structure of the shock interacting with the blast pad surface using high-speed imaging. © 2019 WIT Press

A two-scale approach to widen a predictive blast propagation model around a hemicylindrical obstacle

International audienceThe aim of the present paper was to report on an experimental study of the characterization of a blast wave initiated by a solid explosive and its interaction with a rigid obstacle in the form of a hemicylinder. Pressure transducers located along the path of the blast wave and high-speed imaging allow (1) the measurement of the overpressure at different locations and (2) the characterization of the blast wave inception, propagation, and reflection off the hemicylinder. The scaling effect has been investigated by performing experiments in two different facilities, where one is at twice the scale of the other