Application of shape memory alloy in damage repair of composite materials

Internal cracks will degrade the performance of composite material and even make it fail. In order to solve such problem, the shape memory alloy (SMA) was chosen to be applicated in composite materials for damage repairing. The SMA was firstly assumed to be embedded in the composite material, by discussing the relationship between SMA recovery stress and temperature, and the relationship between composite damage strain and temperature relatively, a theoretical model of damage repair of composite under different initial conditions was then established. Based on this model, the damage repair behaviors of SMA materials under different initial conditions were discussed. The results show that the recovery stress of SMA decreases with the increasing temperature when there is no austenite transformation happens, while increases with the increasing temperature when the austenite transformation occurs. Moreover, the larger the volume fraction of stress-induced martensite in SMA, the greater the maximum recovery stress occurs in the heating process. The happens of the austenite transformation during the heating process can reduce the damage strain of the composite material, and then achieve the purpose of the damage repair. This article can provide theoretical guidance for the future engineering application of SMA in composite damage repair.