Dynamic crushing behavior and energy absorption of graded lattice cylindrical structure under axial impact load

Dynamic behavior of lattice cylindrical structures with triangular and hexagonal configurations subjected to constant velocity impact was studied theoretically and numerically. The dynamic plateau stress of lattice cylindrical shell was well predicted by analytical predictions based on the one-dimension shock theory. The uniform and density gradient lattice cylindrical structures were investigated using finite element models. It was found normalized plastic energy absorption was significantly affected by relative density for two kinds of lattice cylindrical shells. And the ratio of cell wall to skin thickness was found the vital factor determining the specific energy absorption and deformation modes of lattice sandwich cylindrical shell. By introducing density gradient along crushing direction, the results showed that, for lattice cylindrical shell, introducing positive density gradient can enhance energy absorption at the early stage in high velocity. For lattice sandwich cylindrical shell, introducing density gradient can efficiently reduce the peak crushing force but have little effect on the energy absorption.