Dynamic mechanical behavior of foam-core composite sandwich structures subjected to low-velocity impact

The dynamic response of foam-core composite sandwich plates subjected to low-velocity impact is thoroughly investigated by means of drop-weight impact tests and numerical simulations in this paper. The influences of impact energy, foam-core thickness, and punch-head shape and size on the impact mechanical behavior including the impact force time history, the dynamic displacement time history, the residual plastic deformation, the energy absorption capacity, and the back plate deflection are contrastively studied through the control-variant approaches. Several conclusions drawn are useful and helpful to the related product design. The top faceplates of specimens with large foam-core thickness are demonstrated to be vulnerable to the low-velocity impact under stepped levels of impact energy, while large foam-core thickness can reduce deformation of the interior plates effectively. Moreover, among the three representative types of punch heads, the sharper hemispherical one is checked to be the most destructive with the lowest impact force peak. Besides, a finite element model was built to investigate the damage of faceplates and foam cores. The numerical method was proved to be accurate and efficient. A series of results were obtained revealing the damage mode of faceplates and cores under different impact energies.