The axial compression behavior and failure mechanism transition of bamboo-wood composites under quasi-static and low-velocity impact load

Bamboo-wood composites hold promise for impact-resistant applications, yet their dynamic mechanical behavior remains insufficiently understood. This study investigated the axial compression response and failure mechanism transition of bamboo-wood-bamboo (BWB) composites across strain rates of 9.52 × 10⁻⁴ to 208 s⁻¹ . BWB specimens, fabricated from bamboo scrimber and fast-growing Chinese fir, were subjected to quasi-static and low-velocity impact loading. Mechanical properties and failure morphology were systematically analyzed using digital image correlation (DIC), computed tomography (CT), and scanning electron microscopy (SEM), with pure wood as a control. Results demonstrate that BWB exhibits pronounced strain rate sensitivity: the compressive strength increases by 59.1% (from 71.5 MPa to 113.8 MPa) with the increase of strain rate, consistently surpassing that of pure wood. The failure mechanism transitions fundamentally with the increasing strain rate, from a progressive and cooperative mode to an instability-dominated mode. The former failure initiates by wood crushing and interfacial slip under quasi-static loading, while the latter failure characterizes by instantaneous bamboo scrimber buckling and severe interfacial delamination under impact. The volumetric energy absorption of BWB under impact is 160%–227% higher than that of pure wood. This study elucidates the strain-rate-driven transition in failure mode from "progressive cooperation" to "instantaneous instability," providing a theoretical basis for the application of BWB composites in new fields such as the impact-resistant of vehicle, building components and packaging. • Quasi-static and low-velocity impact axial compression behavior of bamboo–wood compositest. • Bamboo–wood composites exhibit significant strain rate sensitivity. • Failure mechanisms transition under different loading strain rates.