Research on broadband electromagnetic wave absorption and load-bearing performance of variable cross-section lattice sandwich structure

The rapid development of broadband electromagnetic weapons and radar technology has imposed an urgent need for multifunctional structures that combine broadband electromagnetic absorption (EMA) and excellent load-bearing performance. This paper proposes a lattice sandwich structure fabricated by 3D printing technology using acrylonitrile-butadiene-styrene (ABS) and ABS mixed with 20 wt% carbon black (ABS/CB). The electromagnetic response of this structure was analyzed by experiments and simulations to explore the broadband absorption mechanism of the lightweight lattice sandwich structure. The structure designed in this paper has an effective electromagnetic absorption (reflection loss ≤ −10 dB) bandwidth of 34.4 GHz and an average absorption rate of 98% in 2-40 GHz. Inspired by the variable cross-section tibia of the stick insect, a lattice sandwich structure with variable cross-section core struts was further devised to enhance the critical buckling load of the structure. The influence of cross-section taper ratios on the limit load of the structure was analyzed using quasi-static compression tests and numerical simulations. The results demonstrated that the specific strength of the structure with the variable cross-section core struts was 86.9% higher than that with the uniform cross-section lattice core struts. A theoretical prediction model for limit load of the structure with variable cross-section core struts was developed.