Low-velocity impact response of 3D carbon fiber reinforced polymer auxetic lattice structures

In this paper, low-velocity impact properties and impact damage responses of a novel type of 3D hybrid auxetic structures made from carbon fiber-reinforced polymer (CFRP) laminates were investigated experimentally and numerically. The structures were first fabricated with three different rib's width ratios t1/t0, and then impacted with three different impact energies of 30, 40, and 50 J using a drop tower impact system equipped with a cylindrical impactor. The finite element (FE) models were built in ABAQUS/Explicit, and the Hashin criteria were applied to predict the failure of the structures. The contact force histories, energy histories, displacements, and failure modes were compared between the experiment and FE simulation at all three impact energy levels. The failure morphologies and mechanisms were obtained and studied. The impact testing results suggest that the 3D auxetic structure with a higher t1/t0 ratio can lead to higher peak contact force and sustain higher impact energy. The failure of the structure starts from the middle area and propagates to the upper and lower areas. This research provides a better understanding of the impact responses and failure modes of the 3D auxetic lattice structure, which can promote the potential applications of the auxetic materials. Highlights Drop weight low-velocity impact responses of 3D novel hybrid auxetic lattice structures are investigated through both experiment and finite element simulation. The effects of structural parameters on the impact performance of the 3D auxetic structures at different impact energy levels are analyzed. The failure morphologies and mechanisms of the 3D auxetic structures are studied.