On the influence of the property gradient on the impact behavior of graded multilayer sandwich with corrugated cores

Graded lightweight structure is a new trend to improve energy absorption capacity of such structural materials. This study aims at the influence of property gradients on the overall behavior of graded multilayer sandwiches with corrugated cores under impact loading. The design of the property gradient of graded multilayer sandwiches as well as the manufacturing of different corrugated cores is presented at first. The graded multilayer sandwich is tested under various experimental configurations at rather low (9 m/s) and high (38 m/s) impact velocities. It turned out that no influence of gradient is found for low impact velocity because a quasi-static equilibrium state is reached. However, at high impact velocity, the test revealed a significant difference between different property gradient profiles. Numerical models are also built to simulate those tests. It allows for the further numerical analysis on a larger range of gradient profiles and higher impact velocities. A general trend for the design of the graded multilayer sandwiches with corrugated cores to improve energy absorption efficiency is proposed, which consists of placing the weakest layer near the protected structure and the hardest layer near the impacted end of the graded sandwich.