Effect of Bamboo Nodes on the Mechanical Properties of Phyllostachys iridescens

Bamboo is a significant natural resource, recognized for its rapid growth, lightweight composition, high strength, and excellent mechanical properties, making it increasingly valuable in the furniture and construction industries. A critical structural aspect of bamboo is its nodes, yet there has been limited research on their impact on bamboo’s mechanical properties. This study investigates the mechanical properties of round bamboo tubes in three different states: internodes (S1), nodes with diaphragm removed (S2), and nodes with diaphragm (S3). The results show that the mechanical properties of S1 are a compressive strength (CS) of 29.72 MPa, a shear strength parallel to grain (SSp) of 11.82 MPa, a radial stiffness (Sr) of 155.59 MPa, an impact toughness (IT) of 20.74 kJ/m2, a modulus of rupture (MOR) of 16.45 MPa, a modulus of elasticity (MOE) of 408.53 MPa, a tensile modulus of rupture parallel to grain (MORT) of 189.62 MPa, and a tensile modulus of elasticity parallel to grain (MOET) of 431.05 MPa. Compared with S1, these above parameters change by CS +11%, SSp 6%, Sr +100%, IT −29%, MOR +5%, MOE +63%, MORT −29%, and MOET −58% in S2 and CS +10%, SSp 28%, Sr +250%, IT −31%, MOR +28%, MOE +92%, MORT −25%, and MOET −42% in S3. It demonstrates that the bamboo diaphragm and nodes significantly influence the mechanical properties of bamboo; they have a significant positive effect on the bending properties across the transverse grain, radial ring stiffness, and shear properties along the grain, but negatively impact the tensile properties along the grain.