Design and evaluation of a modified arrow-head auxetic structure (pinehead) for enhanced energy absorption

Abstract Auxetic structures, known for their negative Poisson’s ratio, exhibit unique mechanical properties that make them suitable for various engineering applications such as load-bearing and energy absorption devices. The Arrow-head is a popular auxetic unit cell with a simple configuration and high stiffness, which has been frequently used in load-bearing applications. However, the Arrow-head has a limitation in its ability to absorb significant values of energy. Therefore, this study presented a novel auxetic unit cell and structure named the Pine-head, which is a modified configuration of the Arrow-head unit cell. The Pine-head structure was designed to enhance energy absorption capabilities while maintaining auxetic behavior. The structures were fabricated using fused deposition modeling additive manufacturing technology and subjected to quasi-static compression loading. Furthermore, the results were verified with the finite element method, showing good agreement between the results. Then, by changing the geometrical parameters of the Pine-head unit cell, two new configurations of Spear-head and Twin Chevron Head (TCH) were introduced. Comprehensive comparisons between three novel auxetic structures and the traditional Arrow-head were conducted in order to study their mechanical properties and assess improvements in their mechanical performance. The results demonstrated that the Pine-head structure exhibited enhanced energy absorption capability compared to the Arrow-head, Spear-head, and TCH structures. The findings of this study suggest that the Pine-head offers significant advantages for high-energy absorption applications.