A novel dragonfly wing shape auxetic tubular structure with negative Poisson’s ratio

Abstract

Mechanical structures abilities to absorb and dissipate energy have a variety of applications in daily life, including the ability to dampen mechanical vibrations and shock effects. In the present study, inspired by the dragonfly wing (DFW) shape, a novel auxetic unit cell was developed with the goal of proposing a novel structure with a lower stress concentrator and consequently increasing energy absorption. The negative Poisson’s ratio behavior was also studied. The DFW shaped unit cells were applied in a tubular structure, and the experimental samples were produced utilizing an additive manufacturing process with polylactic acid filament. To validate the ability to absorb energy of the novel unit cell, a comparison was proposed with the classical reentrant auxetic tubular structure following two different parameters: weight and the number of unit cells being developed in two different DFW structures. The study of the novel unit cell was performed using finite element analysis and experimental testing, and excellent agreement was observed between them. As a result, the bio-inspired DFWs shape in both configurations proposed when compared to the classical reentrant presented an excellent result in terms of absorbing energy, where the structure with the same quantity of unit cells and the structure with the same weight respectively absorb 163% and 79% when compared to the classical Reentrant, finally the new structure presented the negative Poisson’s ratio of −0.5, presenting an auxetic behavior and being able to resist more force and displacement