Performance of honeycomb sandwich structure under combined blast and impact of fragments

The response of sandwich structures under the synergistic effects of blast wave and fragments is a topic of interest for researchers and designers. Thus, the performance of sandwich structure used for enhancing the protection of target structure is numerically investigated because it may experience such complex loading condition occurring due to combined blast and fragment impact. The conventional sandwich structure modelled using aluminum alloy resisted bare blast load imposed on it. But, from the analysis, it is observed that fragments penetrated through front facesheet of the conventional sandwich structure, indicating a lower resistance of front facesheet to combined blast and fragment effects. Thus, behavior of conventional aluminum honeycomb sandwich structures is compared with enhanced sandwich configurations consisting of front facesheet covered with multilayer lightweight composite Kevlar® fabric material. The Kevlar® fabric arrested the maximum number of fragments, and reduced their momentum, thereby reducing the damage level of the sandwich structure. Further, the effect of the charge weight and shape of the fragments on the damage modes of the sandwich structure is also assessed. It is further observed that, with the increase in charge weight, the momentum of the fragments increases, and these penetrate the back facesheet of the sandwich structure.