Mechanical properties of composite bi-directional corrugated sandwich structure

To improve the transverse mechanical heterogeneity of conventional uni-directional corrugated sandwich structures, a new type of bi-directional composite corrugated sandwich structure was designed. Considering the difficulty of manufacturing the bi-directional corrugated sandwich structure, a procese based on vacuum assistant resin infusion (VARI) was proposed for high efficiency and quality preparation. The prepared structures were subjected to compression, bending and shear tests. The failure modes and mechanism of the bi-directional composite sandwich structures were analyzed, the strength and modulus of the structure under different load conditions were obtained, and the comparison between the bi-directional and uni-directional corrugated sandwich structure was made. The results show that the glass fiber/epoxy resin core is the main bearing part under the compression load, and the failure of the structure is mainly reflected in the buckling, fracture and delamination of the core. Under the bending load, caused by the lower compressive strength than its tensile strength of fiber, the upper panel first reaches the failure load under the pressure head. The bending failure modes of the structure are mainly the fracture and debonding of upper panel. The shear failure of the structure is mainly caused by the debonding of the foam and the panel and the collapse of the foam, but the core and the panel are not obviously destroyed. Compared with uni-directional corrugated sandwich structure, the mechanical properties of bi-directional corrugated sandwich structure are significantly improved. © 2021, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.