Experimental analysis of fluid–structure interaction between a blast wave and a sandwich add-on armor

In various situations, targets with different characteristic dimensions are being exposed to blast waves generated by high explosive detonation. One of the existing mitigation methods consists of protecting the target from the explosion with a sandwiched crushable core between a front plate and the target. The pressure generated by the explosion is converted into the planar displacement of the front plate, which compresses the crushable core, delaying the transmission of the load to the target. The influence of the crushable core on the transmitted load in the form of a plateau stress is well described in the literature contrary to its influence on the transferred momentum. In this paper, momentum transmission during the crushing of the core has been experimentally investigated, taking into account the fluid–structure interaction effect, the mechanical behavior of the core, and the pneumatic effects generated by the air trapped into its cells. It is shown that the beneficial effects of fluid–structure interactions are often counterbalanced by the mechanical behavior of the core and that analytical models from the literature are sufficient to describe the order of magnitude of the uniaxial crushing process.