Measurement investigations in tubular structures health monitoring via ultrasonic guided waves: a case of study

Abstract This paper deals with the health monitoring of tubular structures by means of Ultrasonic Guided Waves (UGW) technique. It investigates mainly the stability of measurements, which is a key topic in Structural Health Monitoring. A corrosion-like defect is machined in a full-scale tube and then its size is increased in five steps. Their cross-section areas (CSA) go from less than 1% to around 4.5%. To get a high accuracy, a 3D laser scanner was used to measure these CSAs. The influence of the probe/tube adhesion quality on defect detectability is investigated. Propagation mode type and central frequency are also taken into account. Environmental and operational conditions variations (EOC) are studied too. Regarding the obtained results, it can be concluded that the UGW are an efficient technique for the monitoring of tubes. However, to reach a high-performance level, statistical algorithms are needed to face the problem of EOC and then manage false alarms as reliable as possible. Furthermore, to make data more stable, special care should be paid to the implementation of the sensor, such as glue durability, bonding issues, etc.