Topology optimization of reactive material structures for penetrative projectiles

Recently, reactive materials have been developed for penetrative projectiles to improve impact resistance and energy capacity. However, the design of a reactive material structure, involving shape and size, is challenging because of difficulties such as high non-linearity of impact resistance, manufacturing limitations of reactive materials and high expenses of penetration experiments. In this study, a design optimization methodology for the reactive material structure is developed based on the finite element analysis. A finite element model for penetration analysis is introduced to save the expenses of the experiments. Impact resistance is assessed through the analysis, and result is calibrated by comparing with experimental results. Based on the model, topology optimization is introduced to determine shape of the structure. The design variables and constraints of the optimization are proposed considering the manufacturing limitations, and the optimal shape that can be manufactured by cold spraying is determined. Based on the optimal shape, size optimization is introduced to determine the geometric dimensions of the structure. As a result, optimal design of the reactive material structure and steel case of the penetrative projectile, which maximizes the impact resistance, is determined. Using the design process proposed in this study, reactive material structures can be designed considering not only mechanical performances but also manufacturing limitations, with reasonable time and cost.