Optimization design of a novel microwave absorbing honeycomb sandwich structure filled with magnetic shear-stiffening gel

A novel structural and functional integration microwave absorbing materials (MAMs) are developed, in which MAMs are based on honeycomb sandwich composites filled with magnetic shear-stiffening gel (STG). The microwave absorbing honeycomb sandwich structure (MAHSS) is designed and optimized by simulating microwave absorbing performance, such as flake carbonyl iron particles (FCIP) content and thickness of magnetic STG. It can obtain excellent broadband microwave absorption, in which the reflection loss (RL) from 5.63 to 16.51 GHz is lower than-10 dB for MAHSS with thickness of 1.5 mm and magnetic STG (60 wt%). Furthermore, compared with the pristine honeycomb sandwich structure (PHSS), the bending strength and modulus of MAHSS is improved to 28.2% and 40%, respectively, and the impact energy absorption increased by 26.8%. Finite element analysis based on Coupled Eulerian-Lagrangian (CEL) method was carried out to reveal the intrinsic mechanism of MAHSS impact resistance. The work provides a new idea and method to design and prepare structural and functional integration MAMs with high performance for potential application in weapons and flight equipment.