In-plane mechanical behavior of tri-chiral and anti-trichiral auxetic cellular structures

Abstract

Auxetic cellular structures, characterized by their counterintuitive negative Poisson’s ratio (NPR), have attracted significant attention due to their unique mechanical properties. Their potential for improved energy absorption capabilities makes them promising candidates for applications requiring enhanced resistance to compressive forces. This paper investigates the mechanical response of a specific class of auxetic cellular structures known as chiral auxetics under quasi-static in-plane compressive loading. The study focuses on two distinct chiral structures: tri-chiral and anti-trichiral. A numerical simulation is conducted to evaluate their energy absorption capacities. Numerical results are validated by conducting quasi-static compressive testing of tri-chiral and anti-trichiral auxetic cellular structures fabricated through fused deposition modeling (FDM) 3D printing technique by tuning the printing parameters using Taguchi’s design of experiment approach. Furthermore, parametric investigations are performed to examine the effect of circular node radius and ligament thickness on their energy absorption capacity. The results confirm that tri-chiral auxetic structures shows better energy absorption performance compared to anti-trichiral auxetic structures at the same relative density. The parametric analysis also reveals that variations in node radius and ligament thickness significantly influence the energy absorption performance of these auxetic cellular structures. Finally, the application of tri-chiral auxetics are explored in protective padding structures. The quasi-static experimental testing of the pad structure is conducted to verify the simulated results, while an additional simulation examines localized deformation under constant punching from a rigid hemispherical punch. This incorporation of chiral auxetics in padding structures confirms their applicability in practical applications, demonstrating its potential for broader usage in similar contexts.