High Velocity Impact Damage Assessment of Sandwich Panels With Auxetic Re-Entrant and TPMS Based Cellular Cores

Abstract The architected cellular structures have gained a lot of attention in recent years due to their lightweight, superior and controllable properties. Such lattice structures can be potential candidates for high specific energy absorption applications due to the increase in structural performance. This increase in mechanical properties can be attributed to the gradual and localised changes occurring in the cellular cores. In this study, TPMS sheet-based structures (Diamond), re-entrant auxetic structure (single and double layer) were designed, fabricated, and tested under dynamic loading conditions. Fused Filament Fabrication (FFF) method is used for fabrication of the complex specimens. High velocity ballistic impact tests in the range of 180 m/s to 210 m/s have been carried out for determining the energy absorption, residual velocity and investigation of damage mechanisms. It is also observed that the SEA of the TPMS cores is higher than the auxetic re-entrant cores. There is a significant improvement in impact properties for the sandwich panels upon usage of Kevlar as facesheet on top and bottom of the 3D printed polymer cores. Also TPMS cellular cores with Kevlar as skin possess a very good potential of being used for energy absorption capabilities.