Development of an Integrated Multi-channel Ultrasonic System for Online Structural Health Monitoring of Large Structures

Structural health monitoring (SHM) has becoming one of important issues in the maintenance of various structures such as large steel plates, vessels, and pipes in nuclear power plants. Especially, ultrasonic guided waves have been proposed by many researchers for promising SHM applications because they have ability to travel long distances in the target structures. However, the interpretation of guided wave signals obtained from complex geometrical structures is very difficult. Recently, to address such difficulty, computed tomography (CT) and array methods have been proposed for generating two dimensional images of plate-like structures using spatially distributed ultrasonic transducers. We developed an integrated multi-channel ultrasonic system that can handle array transducers and carried out experiments by using the developed system to construct CT images of a defect in a specimen.