On low-velocity impact behavior of sandwich composites with negative Poisson's ratio lattice cores.

• Low-velocity impact behavior of a new sandwich composite structure with negative Poisson's ratio lattice cores is studied. • A finite element analysis strategy is employed to investigate the mechanical response and energy absorption efficiency. • The sandwich structure with negative Poisson's ratio lattice cores can better disperse the concentrated impact load. • The impact location has certain influences on the energy absorption performance in different impact energy zones. In order to investigate the low-velocity impact performance of a new type of sandwich composite structure with negative Poisson's ratio lattice cores, low-velocity impact tests were carried out using the sandwich composite specimens, which were prepared by 3D printing lattice cores and glass/epoxy composite sheets. A finite element dynamic analysis strategy was also employed to investigate the mechanical response, the total energy absorption, and energy absorptivity of the sandwich panel at impact energies of 5 J, 10 J, 15 J, 20 J, 30 J and 40 J, respectively. Results show that the new sandwich structure can better disperse the concentrated impact load received by the upper sheet and dissipate most of the impact energy in the process of transferring the loads during cushioning. The negative Poisson's ratio lattice structure can guide damages, and it is found that the position of the impact point will affect the impact mechanical response and energy absorption ability of the sandwich panel. [ABSTRACT FROM AUTHOR]