Fracture Mechanism of Shell with Reactive Materials Filled Structure Subjected to Multiple Impacts and Internal Deflagration Loadings

The reactive materials filled structure exhibits the unique characteristics of multiple deflagrations, layer-by-layer fracturing, and spatially distributed energy release when penetrating multilayered plates, and its layer-by-layer energy release characteristic is significantly influenced the fracture behavior of the shell. To reveal the fracture behavior and failure mechanism of shell with the reactive materials filled structure subjected to multiple impacts and internal deflagration loadings, a stress distribution model for the shell is developed, and the experiment on the penetration of reactive materials filled structure into a double-layered plate is performed. The typical fractures of the recovered fragments are macroscopically and microscopically analyzed. The results show that a novel stress reverse effect appears along the axial direction of the shell under the impact and internal deflagration loadings, which means that the axial stress converts from compressive to tensile stress, and the shell fractures when reaching the tensile stress limit. The circumferential fracture dominated by internal deflagration pressure occurs, causing the cylindrical segment be fractured into multiple pieces. The SEM images and fracture morphologies of the recovered fragments from different regions verify that the fracture mechanism of penetration structure shell is influenced by two loadings: axial failure dominated by impact loading induced the reduction in penetration structure length, and circumferential failure dominated by internal deflagration loading leading to the disintegration of shell. Additionally, Interior and outer area ratio S_in / S_out has an influence on the resistance to internal deflagration loading significantly, and the initial impact velocity and internal deflagration pressure exhibit opposite effects on the fracture length.