Blast response study of the sandwich composite panels with 3D chiral auxetic core

Chiral auxetic cellular structures were fabricated from Ti6Al4V alloy using the Selective Electron Beam Melting method, and tested experimentally under quasi-static and dynamic compression loading conditions. The experimental results were used to validate built computational models of auxetic cellular structure in LS-DYNA. The models were used to study the geometry effect on the Poisson's ratio of the analysed chiral auxetic structure. The response of sandwich composite panels with auxetic core under blast loading was studied extensively computationally, where the maximum panel displacement and the Specific Energy Absorption (SEA) of the composite panel were evaluated. Three different methods for blast loading (ConWep, Smooth Particle Hydrodynamic, Multi-Material Arbitrary Lagrange-Eulerian) were compared and validated based on the experimental data. It was determined that larger thickness of the cover plate lowers the panel maximum displacement, while the SEA is larger when thinner cover plates are used. Also, it was shown that the chiral unit cell amplitude effect on the maximum displacement and SEA is, in most analysed cases, negligible in comparison to the cell length effect, which is more prominent. The presented study illustrates great potential of using sandwich structures with designed auxetic cellular cores to improve the response of modern composite structures to blast loading.