Bending-Dominated Auxetic Materials for Wearable Protective Devices Against Impact

Auxetic metamaterials have high energy absorption capacity and indentation resistance, due to their significant densification mechanism during compression. This study investigates the performance of structured materials in layered thin plates, with potential applications in wearable protective devices for sport activities. Two different 3D lattices, conventional and re-entrant honeycomb, are studied in detail and their dynamic behaviour is compared with that of a 2D auxetic lattice. Initially, the equivalent elastic properties of the proposed geometries are investigated at varying equivalent densities. Then a new lightweight solution of a sandwich structure with an auxetic metamaterial core is proposed for possible application to facial protective masks. Numerical impact analyses of the problem show the potential benefit of the present proposal with respect to traditional mask geometries.