Abstract: Bamboo is an important building material with natural hygroscopicity, and the mechanism of water effects on its deformation and fracture behavior has not been fully revealed. For this purpose, a novel in-situ testing method was developed in this study, which coupled Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques. This method was used to investigate the effects of various Moisture Content (MC) levels (0, 6%, 15%, and 25%) on the tensile behavior of bamboo. The results showed that as the MC increased from 0 to 25%, the tensile strength of bamboo decreased from 163 to 110 MPa, the Young's modulus dropped from 8.5 to 3.9 GPa, and the elongation increased from 4.3 to 14%. An increase in MC could effectively promote the occurrence of subcritical cracks and micro-interfacial dissociations in bamboo. The synergistic effect of these two factors facilitated strain dispersion, ensuring adaptability to large deformations. Additionally, it was found that an increase in MC could significantly alter the fracture mode. This ingenious synergistic effect in bamboo was revealed for the first time in this study. The mechanisms discovered in this study may provide some important insights into the design and fabrication of advanced biomimetic heterostructures and biomimetic interfacial materials.

Key words: Moso bamboo')">Moso bamboo, Deformation, Fracture behavior, Acoustic emission, Digital image correlation, In-situtesting