The bending of 3D-printed bio-inspired sandwich panels with wavy cylinder cores

Beetle Elytron Plates (BEPs) represent a new class of biomimetic sandwich cores with excellent mechanical properties inspired by the microstructure of the beetle elytra. The cores have a hexagonal centre-symmetric configuration with through-thickness cylinders in the unit cell. In this work, we describe the behaviour of sandwich panels with novel BEP core configurations possessing wavy cylinders under four-point bending tests. Full-scale simulations are also carried out to validate the experimental data. The results show that all the sandwich panels produced with face skins adhesively bonded have material failure earlier than the adhesive bond failure. BEPs with wavy cylinders have larger peak loads compared to those with straight cylinders, and all BEPs show higher peak loads than those of sandwich panels with classical hexagonal honeycombs. Additionally, all the BEPs exhibit an enhanced ductility compared to honeycomb sandwich panels.