Structural enhancement and repair of CFRP T-joint by the cross-embedded SMA wire

Owing to shape memory and super-elasticity, shape memory alloy (SMA) has been applied widely in many fields, such as aerospace, medical facility, civil engineering, and so on. In this paper, wires of nickel-titanium (NiTi) SMA are inserted into the carbon fiber-reinforced polymer (CFRP) T-shape structure. The enhancing laws are investigated via the comparison of the performance of the cases with or without SMA in tensile tests. According to the microscopic damage morphology and the damage degree in the simulative study, the reinforcement mechanism is further revealed. Then, the roles of the SMA in the adhesive repair of the T-joint with permanent damage, dominated by delamination, are analyzed by contrast experiments. Overall, both the advantage of SMA, super-elasticity and shape memory, are skillfully utilized to improve the mechanical property and subsequent adhesive repair of CFRP T-joints. Specifically, it raises by an average of 10% and 85% the value of ultimate force and elongation for T-joint cross-embedded with SMA compared with no SMA's, as well as increasing by 57.14% and 42.42% the number of ultimate force and healing efficiency by embedding SMA under thermal adhesion environment averagely.

Automated summary

This paper investigates the application of shape memory alloy (SMA) in carbon fiber-reinforced polymer (CFRP) T-shape structures. Through tensile tests, the enhancing laws and reinforcement mechanisms are revealed. The roles of SMA in adhesive repair of permanent damage in T-joints are analyzed. Overall, SMA's advantages of super-elasticity and shape memory are utilized to improve the mechanical properties and adhesive repair of CFRP T-joints.