Mechanical Properties of a Novel Composite Longitudinal‐Teeth Tubular Connection: Experimental and Numerical Study

ABSTRACT

To overcome the damage to fiber continuity in the connection region of conventional composite tubular joints, as well as the limited pre‐tightening level, this study proposes a shape memory alloy (SMA)‐prestressed longitudinal‐teeth tube connection (LTTC). Pre‐tightening monitoring tests and axial tensile tests were conducted to characterize the mechanical response of the LTTC. A three‐dimensional finite element model incorporating the thermomechanical phase transformation behavior of the SMA was then established and validated against the experimental results. On this basis, a parametric analysis of the load‐carrying performance of the LTTC was carried out, and the effects of the key design parameters were further quantified. The results indicate that the LTTC can establish a stable radial pre‐tightening state and achieve effective axial load transfer. The longitudinal teeth enhance geometric constraint and interfacial load transfer, thereby enabling more efficient utilization of composite material strength. The tested specimens achieved an ultimate tensile capacity of 1111 kN and a connection efficiency of 93%, with failure governed by tensile fracture of the CFRP longitudinal‐teeth tube rather than interfacial slippage. These results indicate that the longitudinal teeth provide effective resistance to interfacial slippage, allowing the joint failure to be governed by composite material strength rather than friction‐limited behavior.