Links between material pair and energy absorbing capacity of lattice-cored sandwich: A comparison study

Excellent energy-absorbing capacities have been a long-standing requirement for structures in the field of transportation and aerospace, and tension–torsion coupling (TTC) metamaterials have seen promising application opportunities since their emergence. In the current work, we carry out a systematic study on the metamaterial-cored sandwich under impact. Emphasis have been put on revealing the links between the material pair (that of the lattice core and cover sheets) and the energy-absorbing capacity, from both the numerical and experimental points of view. It is disclosed that the mismatch between the stiffness moduli of the lattice core and the cover sheet can alter the deformation mode of sandwiches under impact load, and hence have a significant influence on the energy-absorbing capacity of the sandwich. The change in energy absorption ratio at various impact energy levels is also investigated. Lastly, a graded TTC metamaterial optimization is conducted for the sandwich core by carefully tuning its dimensions and the resulting stiffness, as a means to be compatible with the impact energy and the paring effect of constituents materials.