Optimized design, fabrication, and enhanced performance of honeycomb sandwich structure for excellent impact resistance and broadband microwave absorption

Lightweight microwave absorbing structures have wide applications in aerospace and military equipment. In general, honeycomb sandwich structure is regarded as an ideal choice. However, traditional honeycomb sandwich structure designs have limitations in improving absorption bandwidth, and their impact resistance remains unremarkable. Herein, a novel microwave absorbing honeycomb sandwich structure (MAHSS) has been thoroughly investigated through both theoretical and experimental validations. The MAHSS is crafted using a glass fiber (GF)/epoxy composite that is coated with reduced graphene oxide (RGO) for enhanced performance. The middle honeycomb layer of MAHSS is arranged transversely to add more interface. When the honeycomb core has 2 layers and a wall thickness of 2.4 mm in MAHSS, the maximum achievable bandwidth is 13.6 GHz, while the minimum reflection loss (RL min ) reaches −24.02 dB under TE mode. The mechanical properties of the MAHSS were evaluated by compression test and drop weight impact testing. The MAHSS exhibits excellent compression and impact resistance, accompanied by self-recovery performance post-unloading. It still did not penetrate under an impact energy of 150 J, absorbing up to 123 J of energy. This work provides theoretical guidance and technical support for designing and preparing structural and functional integration microwave absorption materials.