Mechanical behavior of graded combined auxetic-honeycomb structures

Various methods such as geometry changes can improve the energy absorption of auxetic structures. In this article, the mechanical behavior of graded combined auxetic-honeycomb structures is investigated through various models of grading. In the graded angle method, the best samples are selected for construction and experimental after performing numerical simulations, and this method comprises both the all-auxetic and honeycomb-auxetic graded angle techniques. Additionally, it is proven that energy absorption can be further increased by adding a reinforced core to the cells of the re-entrant structure. Finally, optimal models for energy absorption are developed by combining the best models of graded angle, graded thickness, and reinforced core. The best of them is the all-auxetic unilateral graded angle with rhombic core auxetic (UGA-A) +(RCA) sample with energy absorption that is three times higher than HAR, which can be utilized in various industrial and sports applications.