Enhancing bending performance in 3D woven spacer composites with lightweight biomimetic integrated double-spacer structure

Three-dimensional woven spacer composites (3DWSCs) with lightweight and excellent mechanical properties have promising application in communication, transportation, aerospace and other fields. However, traditional single layer 3DWSCs exhibit insufficient strength, especially when dealing with high thickness, as the pile yarns tend to buckle. In this study, inspired by the structural features of the Thalia dealbata, 3D woven integrated double-layer glass fiber/epoxy resin spacer composites by mimicking were fabricated. Innovative integrated double-layer structure design effectively improves the performance and failure mode of 3DWSCs under bending loads. Compared to single-layer 3DWSCs, the resulting double-layer 3DWSCs exhibited a 41.79% increase in peak bending load, a 46.85% increase in bending stiffness, and a 99.38% increase in energy absorption. In addition, the double-layer 3DWSCs showed a low density of 0.52-0.55 g/cm3. This work introduces bioinspired double-layer 3DWSCs with characteristics of lightweight and superior bending performance, potentially offering novel ideas for the design of high-performance composites. Highlights center dot Inspired by the structural features of the Thalia dealbata, a 3D integrated woven double-layer glass fiber/epoxy resin spacer composites by mimicking were fabricated.center dot 3D woven double-layer spacer composites are lightweight (0.52-0.55 g/cm(3)) and can effectively improve the bending properties of single-layer structures.center dot Based on the analysis of the fracture morphology, the significant improvement of the fracture pattern of the single-layer structure by the double-layer structure is effectively demonstrated.center dot This study introduces novel design strategies for multi-layer lightweight composite materials and holds broad applications.