Corrosion Monitoring of a Water Supply Pipe Using a Circumferential Guided Wave Magnetostrictive Patch Transducer System

In this study, a circumferential guided-wave system with a magnetostrictive patch transducer (MPT) was employed to monitor the changes in ultrasonic wave signals that occur in accordance with the corrosion in water supply pipes. A series of laboratory experiments were performed to confirm the effectiveness of the system, which was installed on water supply pipes. We demonstrated that the MPT generated and measured circumferential shear-horizontal (SH) waves effectively at a certain frequency and axial position without being affected by the liquid inside the pipes. We conducted experiments by filling pipes with a specific chemical fluid chosen to generate corrosion defects on their inner surface. The MPT system was installed on the pipe and measured SH waves for 30 days. The amplitudes of SH wave signals linearly decreased with time as the corrosion built up on the inside of the pipes. The results showed that the system can be used as a tool for monitoring the corrosion status along the circumferential path in the pipe. More practical studies will be conducted for in-service monitoring of water supply pipes.