Dynamic performance of arc-shaped auxetic structures through split Hopkinson pressure bar tests

Abstract

This study investigates the mechanical behavior of auxetic energy-absorbing structures with arc-shaped members under dynamic loading. Four configurations namely RED, Multiple-Arc, REC-Star, and REC-Flower were designed and evaluated. The Multiple-Arc and RED structures were fabricated using fused deposition modeling and tested via Split Hopkinson Pressure Bar experiments, while all structures were analyzed using finite element modeling. The experimental results demonstrated good agreement with numerical simulations, validating the accuracy of the FE approach. Also, the energy absorption (EA), specific energy absorption (SEA), and Poisson’s ratio of the structures were compared. The Multiple-Arc structure exhibited the highest EA and SEA due to its arc-shaped internal members, which enhanced stress transfer and impact dissipation. The REC-Flower structure also performed well, benefiting from curved members that reduced stress concentration. Conversely, the RED structure, lacking internal members, showed the lowest EA due to inefficient wave transmission. The REC-Star structure initially displayed high EA but experienced premature failure due to stress concentration at sharp corners. These findings emphasize the significance of curved internal member arrangement in optimizing auxetic structures for dynamic applications. The results provide insights into designing auxetic materials with tailored EA and deformation characteristics for impact-resistant applications.