Self-sensing joints for in-situ structural health monitoring of composite pipes: A piezoresistive behavior-based method

Abstract

Composite pipes have been widely applied in various fields, and their structural health monitoring has garnered widespread attention. In this study, self-sensing joints were manufactured using conductive composites. By monitoring the electrical resistance of the joints, a piezoresistive behavior-based self-sensing method for composite pipes was developed. First, the self-sensing method was evaluated through cyclic internal pressure tests, and the monitoring resistance exhibited sensitive and timely responses to the internal pressure of composite pipes. Compared with strain gauges, the method demonstrated a sensitivity improvement of up to 90 times. Subsequently, the self-sensing method was applied to monitor joint damage, and a sharp increase in monitoring resistance was observed prior to joint failure. Furthermore, a strong correlation between the monitoring resistance and the degree of joint damage was demonstrated. The results demonstrated that pipe joints are structurally safe when the monitoring resistance change remains below 275 %, which corresponds to the elastic deformation of pipe joints. The pipe joints are considered damaged when the monitoring resistance change exceeds 4908 %. Overall, the self-sensing method proves to be capable of capturing damages inside pipe joints, presenting a promising approach for in-situ structural health monitoring of composite pipes.