Development of Drone-Based Remote AE Measurement Systems

Abstract

Large-scale plants and infrastructure facilities consist of numerous structural components that are susceptible to various types of damage during long-term service. Periodic inspections are essential to ensure structural integrity; however, inspection efficiency is increasingly constrained by limited accessibility, high costs, and a shortage of skilled inspectors. Consequently, the development of efficient and cost-effective condition monitoring technologies is strongly required. Although acoustic emission (AE) measurement is effective for damage detection, conventional AE measurements require sensor installation at elevated or hard-to-access locations, resulting in safety and operational challenges. To address these issues, a remote AE measurement system was developed by combining a digitizer with noise reduction functions and an AE sensor mounted on a drone. In this study, two types of remote AE measurement systems were constructed: a contact measurement system using a conventional AE sensor with a dry couplant, and a non-contact AE measurement system using an air-coupled ultrasonic sensor. The detection sensitivities of the two systems were experimentally compared. Results obtained from measurements using an artificial AE source generated by a Hsu–Nielsen source on a steel plate demonstrated that both systems were capable of detecting AE waves with a high signal-to-noise ratio.