Quasi-static crashworthiness behaviour of auxetic tubular structures based on rotating deformation mechanism

Abstract

Auxetic materials have attracted significant interest due to their exceptional mechanical characteristics and distinctive deformation modes. Nevertheless, the practical use of these materials in engineering is constrained by their limited ability to absorb energy. Thus, enhancing the energy absorption (EA) capabilities of auxetic materials is crucial to expand their range of potential applications. In this study, the EA capabilities of auxetic tubular structures with rotating deformation mechanisms are examined, with a specific emphasis on three different perforation shapes: elliptic, peanut, and square, along with their modified versions incorporating stiffeners. The study employs a combination of experimental testing and numerical modelling, utilising ANSYS/LS-DYNA to evaluate various crashworthiness parameters. These parameters include total EA, specific EA, maximum crushing force, and crushing force efficiency, all of which are assessed under quasi-static compression conditions. The research highlights the importance of perforation shape and stiffener incorporation in enhancing crashworthiness. Results show that elliptic perforations exhibit superior EA and stiffened auxetic models outperform conventional ones in terms of crash absorber performance. The presence of stiffeners significantly improves the ability of tubular structures to withstand crushing forces. Furthermore, the study validates the numerical model against experimental findings, demonstrating a high level of agreement in terms of crushing force–displacement, EA, and failure modes. The research provides valuable insights into the design and performance of crashworthy structures and offers potential applications in various fields where impact resistance and EA are critical.

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“…squares). Furthermore, when including a stiffening strut to the same structures studied, results showed increased structural stiffness and reduced SEA [18,19]. Other works observed differences in the SEA when comparing two different 3D strut-based structures, and their effect when creating a composite-metamaterial with the union of both unit cell types [20].…”

“…The amount of energy absorbed by a lattice structure has been widely explored by several groups since it is one of the most interesting features for biomedical implants, multi-impact activewear, or crashworthiness applications. Solka and Orhan (2024), studied the mechanical performance of honeycombs in cylindrical planes [19]. They showed increased Specific Energy Absorption (SEA) in honeycombs featuring round pores (i.e.…”