Multiscale physicomechanical response and energy mitigation of bamboo scrimber: The regulatory role of bamboo bundle fluffing intensity

As a structural bio-composite, bamboo scrimber (BS) exhibits significant potential for load-bearing applications. However, the regulatory role of the fundamental structural unit's (bamboo bundle) fluffing intensity in determining its multiscale performance remains inadequately understood. This study systematically investigates the influence of three fluffing intensities on BS (BS L , BS M , and BS H ) multiscale physicomechanical response and energy mitigation capacity under both quasi-static and high-strain-rate loading. Results indicate that fluffing intensity is a decisive parameter in modulating the fiber-matrix interface and internal micro-architecture. Specifically, BS M achieved an optimal synergy between fiber structural integrity and resin impregnation, yielding peak MOR (130.3 MPa), MOE (18.7 GPa), vertical and horizontal shear strength (21.9 MPa and 22.1 MPa), and superior dimensional stability. A pronounced compressive anisotropy was identified; longitudinal strength peaked at BS M while transverse responses exhibited divergent axial trends across X, Y, and Z directions. Fluffing intensity also impacts dynamic behaviors; tensile and compressive strengths follow a non-monotonic evolution, peaking at 119.8 MPa and 246.7 MPa for BS M , respectively. Furthermore, BS M optimizes kinetic energy conversion during impact, achieving peak energy absorption (14.5 J) and minimum maximum impact energy (30.9 J). These findings elucidate intrinsic structure-performance relationship, providing critical theoretical guidance for the design of high-performance bio-composites.