Ballistic impact response of reinforced honeycomb sandwich panels

Abstract

Abstract Honeycomb sandwich panels are extensively adopted in a wide range of structures including aircraft, ships, automobiles, and infrastructure for being lightweight and occupying high out-of-plane compression and out-of-plane shear properties. They are evenly popular for their attractive energy absorption capability and resistance to ballistic impacts. Reinforcement of the hexagonal honeycomb panels is an efficient way to improve the impact resistance. However, a detailed study on the reinforcement types against ballistic impacts has not yet been reported. Therefore, the current research investigates the improvement of total energy absorption, ballistic limit velocity, and specific energy absorption (SEA) of three different reinforced hexagonal honeycombs, namely, triangular, circular, and hexagonal reinforcements against high-velocity blunt impacts. A parallel study is also carried out without any reinforcement and only thickening the cell wall of the non-reinforced hexagonal honeycomb panel. A numerical approach is adopted with commercial finite element code Ansys Explicit to analyze the virtual impact cases. The plate of the honeycomb panel is assumed as aluminum alloy Al-7075-T6, while the honeycomb core is made of Al-5083-H116. For both the alloy variants, Johnson-Cook flow stress parameters are utilized. For the projectile, a blunt cylindrical-shaped structural steel bullet is considered. It is found that, for the current investigations, triangular and circular reinforcements can significantly improve the overall ballistic performance of the sandwich panels with a penalty of weight increment. However, thickening the cell wall of the hexagonal core without any reinforcement exhibits the best ballistic performance.