Mechanical behavior and damage mechanisms of woven bamboo strip reinforced epoxy resin composites

The heterogeneous multiscale anatomy of bamboo culms induces pronounced property anisotropy, necessitating tailored architectural design and systematic performance assessment. This study fabricated a bamboo-woven reinforced epoxy resin composite utilizing bamboo strips sourced from distinct radial location via vacuum-assisted resin transfer molding . Comprehensive mechanical evaluation revealed pronounced radial-position-dependent variations in composite properties. Strips from peripheral regions synergized the high tensile strength of bamboo fibers with enhanced matrix interlocking in the middle lamellae region, achieving optimal tensile (120 MPa) and flexural strengths (209 MPa). Conversely, internally sourced strips, characterized by larger vascular bundle diameters , increased the critical energy barrier for fiber pull-out through mechanical interlocking, resulting in composites with outstanding impact strength (57.9 kJ m −2 ). A novel mid-layer displacement analysis method was developed to quantify interfacial adhesion behavior. Fractographic analysis identified three dominant failure modes: fiber-matrix debonding (Mode I), interlaminar shear failure (Mode II), and tangential matrix cracking (Mode III). The established structure-property relationships provide fundamental insights for biomimetic design of sustainable natural fiber composites , particularly in optimizing hierarchical structure through radial gradient engineering. This research uncovers the correlations between the gradient alterations in the content and wettability of bamboo fiber bundles and the mechanical properties and fracture behavior of bamboo, thereby offering a theoretical foundation and insights for the development of novel bamboo-based engineering materials , the bionic design of bamboo-inspired structures, and the structural optimization of fiber-reinforced composite materials • Quantified multilayered radial gradient in bamboo vascular bundle content/structure. • WBC-2 shows peak tensile (120 MPa) and flexural strength (209 MPa) performance. • WBS-4 shows the best impact strength and less instantaneous structural failure. • Microstructural gradient evolution governs macroscopic mechanical properties.