The development of the lightweight sandwich plate with periodically repeated cores is one of hot issues to reduce the weight of the part. The behavior of the sandwich plate under static and dynamic loads is greatly influenced by the design of the cores. The aim of this paper is to investigate the effects of the corrugated angle on low velocity impact characteristics of the lightweight sandwich plate with corrugated cores. The corrugated core with the fold surface is designed to improve the joining characteristics between cores and skin sheets. The corrugated angle of the corrugated cores ranges from 45o to 90o. Specimens are manufactured from the fused deposition modeling (FDM) process. The characteristics of the fabricated specimen are investigated. Impact experiments are performed using a drop impact tester with a stretching type of fixture and the hemispherical nose of the impact head. From the results of the experiments, the influence of the impact energy and corrugated angle on the failure pattern of the lightweight sandwich plate is examined. The effects of the corrugated angle on critical impact energies for different failure patterns are investigated. Finally, the failure map of the lightweight sandwich plate with corrugated cores is estimated.

In this study, a numerical analysis on the impact response of HHA (High Hardness Armor Plate) sequences under a 7.62 mm projectile impact was performed to obtain the fundamental design data for a combat-vehicle platform. Recently, the ballistic-protection levels for combat vehicles have increased, and ballistic-protection designs should now be able to deflect multi-hit projectiles. To study the ballistic-impact characteristics, armor-plate sequences of one or two layers with a gap of 0 mm to 2 mm between the front and rear plate were defined under the same weight and thickness. For the certification of the reliability of the numerical model, ballistic tests and an analysis of the single plate under the 7.62 mm projectile impact were performed and analyzed. On the basis of a valid numerical model, a numerical analysis was performed and analyzed. Lastly, it was proved that the performances of the two-layer sequence with the 2 mm gap regarding the impact-response acceleration, deflection efficiency, and penetration depth are the highest.

The goal of this paper is to investigate the effects of out-of-plane deposition angle on product characteristics of a UV photo-curing process. Specimens are manufactured from a commercialized UV photo-curing machine, the NOBEL V1.0. The influence of the out-of-plane deposition angle of the specimen on surface characteristics, including morphology of the sloped surface, pick-to-pick distance of convex region, and roughness of the sloped surface, is examined via the observation of the sloped surface. In addition, the influence of the radius of curvature of the specimen on the surface roughness of the sloped surface is evaluated. The effects of the out-of-plane deposition angle on impact strength of specimens are investigated via Izod impact experiments. Finally, we discuss the influence of the out-of-plane deposition angle on failure characteristics of specimens for impact loads.