Core and panel types affect the mechanical properties and failure modes of the wood-based XX-type lattice sandwich structure

Composite lattice sandwich structures have the characteristics of light weight and high strength. In this study, a wood-based XX-type lattice sandwich structure was fabricated by a type of insertion-glue method, using wood-plastic composites (WPC) and oriented strand boards (OSB) as panels, and birch and glass-fiber reinforced plastic (GFRP) as cores. The mechanical properties and failure modes of the wood-based XX-type lattice sandwich structure were examined by an out-of-plane compressive test, a short beam shear test and their corresponding analytical models. Analytical models and failure modes were used to find the optimal mechanical properties of the wood-based XX-type lattice sandwich structure combination. The results from the out-of-plane compressive test and the analytical model showed that the failure modes of the combination of WPC + GFRP and OSB + GFRP were primarily panel failures, while the failure modes of the combination of WPC + birch and OSB + birch were primarily core shear failures. The specific strength and modulus of the structures built by the combination of OSB + GFRP were larger, which are more in line with their characteristics of light weight and strong strength. The short beam shear properties of the combination of OSB + birch were better, and the failure modes were lamination and core breakage. Thus, the overall short beam shear property of the combination of OSB + birch was better than that of the combination of WPC + GFRP, and the combination of OSB + birch was more suitable for the short beam shear theoretical model.