Analytical Study on the Transverse Stress Model and Its Influencing Factors on Moso Bamboo

Conventional building materials predominantly rely on non-renewable resources, while the exploration of high-performance and renewable alternatives exhibits the potential for sustainability. Bamboo offers excellent renewability, mechanical properties, and eco-friendliness; however, the susceptibility to cracking impedes its application, especially for long-term structural requirements. The cracking primarily occurs when tangential tensile stresses on inner/outer surfaces exceed the transverse tensile strength of bamboo. This study addresses the issue of transverse cracks in Moso bamboo (Phyllostachys edulis) by proposing and validating a tangential stress prediction model based on the theoretical model of transverse stress in standard circular rings. A correction factor K was determined through finite element analysis to account for the non-standard circular ring shape of bamboo and the presence of the bamboo culm base. Using Moso bamboo samples aged 1 to 7 years, experiments were conducted under varying temperatures (35 °C, 45 °C, and 55 °C) and humidity levels (30%, 50%, and 60%) to measure the initiation and propagation of cracks under tangential stress. Based on experimental data, a functional relationship was established between the internal and external surface strains of bamboo and factors such as bamboo age, geometric dimensions of the bamboo ring, temperature, and humidity. This model can calculate the tangential stress of bamboo based on bamboo age, geometric dimensions of the bamboo ring, temperature, humidity, tangential/radial elastic modulus ratio, and water loss time. It provides a theoretical foundation and engineering reference for predicting and preventing cracking in Moso bamboo.