Static and dynamic mechanical behaviors of bamboo scrimber under combined tension-bending

Bamboo scrimber is a material with significant potential in the construction industry. In the context of its application as a beam structure, bamboo scrimber experiences combined tension-bending rather than single load. Furthermore, potential factors such as earthquakes, crosswinds, and progressive collapse events can induce static and dynamic deformations at varying loading rates in the structure. Up to now, the static and dynamic deformation behavior of bamboo scrimber under combined tension-bending has not been fully understood. The aim of this study is to investigate the effects of loading rate and pre-tension force on the mechanical behavior of bamboo scrimber through experimental research. The experimental results show that, both loading rate and pre-tension force will impact the mechanical behaviors of bamboo scrimber. Increasing the loading rate leads to an increase in the maximum bending load, bending fracture deflection, total fracture strain, and total dissipated energy. Increasing the pre-tension force will cause an increase in the maximum bending load, effective bending modulus, and total dissipated energy. The fracture positions become more random with the increase in pre-tension force. SEM fracture analysis shows loading rates and pre-tension forces has significant influences on the fracture mechanism. The fracture mode transitions from delamination dominated to fiber/matrix fracture dominated as pre-tension force rises from 0 N to 6000 N. This research offers valuable guidance for the practical implementation of bamboo scrimber beam in engineering applications. The findings provide data support for the design of fiber-reinforced composite and biomimetic bamboo structures subjected to complex stress conditions.