Blast response and multi-objective optimization of elliptic annular re-entrant honeycomb sandwich panels

Terrorist attacks and armed conflicts pose a threat to people's lives and property through explosive impacts. The design of protective structures that meet the complex requirements of real-world environments and combine excellent mechanical performance with lightweight characteristics is becoming increasingly important. This study proposes a blast protection sandwich structure incorporating an elliptical annular re-entrant (EARE) honeycomb. A validated numerical model was used to investigate the response behavior of EARE honeycomb sandwich panels under explosive loading. The explosive response process of EARE honeycomb sandwich panels was divided into three phases. In the first and second phase, the elliptical ring structures in the cells provided support to the faceplate and diagonal ribs, restricting further collapse of the cells and overall deflection of the sandwich panel. This enhanced the explosive protection performance of EARE honeycomb sandwich panels. The study also parametrically investigated the explosive protection performance of EARE honeycomb sandwich panels under different design and loading variables. The results indicate that under larger explosive loads, the honeycomb core and backplate play a more significant role in the explosive protection performance of the sandwich panel. Increasing the stiffness of the sandwich panel by changing design variables reduces the maximum residual deflection (MaxD) while decreasing the specific energy absorption (SEA) of the sandwich panel. Finally, to balance the explosive protection performance and mass of EARE honeycomb sandwich panels, a multi-objective optimization was conducted. Compared to the baseline model under the same load, the optimized EARE honeycomb sandwich panel achieved a 68.70 % increase in specific energy absorption (SEA) and a 33.00 % reduction in mass. This study demonstrates the potential application of EARE honeycomb sandwich structures in the field of blast protection. Optimizing the design parameters of EARE honeycomb sandwich structures can further meet the lightweight requirements of application environments.