Low-velocity impact response of a thin sandwich plate with a metallic sheared dimple core subjected to a free boundary condition

Various studies of the impact and crushing characteristics of sandwich plates with metallic structured cores have been undertaken to apply sandwich plates to structural materials of transport vehicles. The goal of this paper is to investigate into low-velocity impact responses of a thin sandwich plate with metallic sheared dimple cores subjected to a free boundary condition through drop impact experiments. In order to examine the influence of the impact parameter, including the impact energy and the nose diameter of the impact head, on the deformation, failure and energy absorption characteristics of the thin sandwich plate in a free boundary condition, drawing type drop impact experiments have been performed. The results of the experiments have been shown that excessive extension of the sheared section and significant crushing of the core as well as excessive deformation of the front face-sheet in the vicinity of the impacted region commence when the nose diameter is 20 mm and the impact energy is larger than 65.3 J. In addition, it has been noted that the energy absorption rate of the thin sandwich plate is influenced by the core compressive strain and that the core crushing should be reduced to improve the energy absorption characteristics of the thin sandwich plate. The performance and benefits of the thin sandwich plate have been discussed through the comparison of the thin sandwich plate with a DP780 monocoque plate. From the results of the comparison, it has been shown that the thin sandwich plate can improve energy absorption characteristics in spite of the reduced weight and weaker properties. (C) 2011 Elsevier B.V. All rights reserved.