Testing of Permanently Installed Piezoelectric Ultrasonic Guided Wave Transducers for Structural Health Monitoring

Abstract

Abstract Guided wave ultrasound can propagate large distances and enables the use of permanently installed piezoelectric transducers in structural health monitoring systems. The transducers can be exposed to harsh operating and environmental conditions, and it is advantageous to have a method for checking the operation of transducers during installation and later system maintenance. In monitoring applications, measurements may be compared with previously captured measurements and changes in the signals are used to detect defects. This process is limited by environmental changes and changes in the performance of the transducers. Measurements that can be performed in the field to check the performance of installed transducers are considered. These measurements include electrical impedance measurements and the transmitting response of the transducers. The initial development of a portable and low-cost instrument for performing these measurements on piezoelectric transducers for rail track monitoring is described. This instrument allows a transducer to be tested before and after installation and at later dates. If measurements of installed transducers are performed regularly, it will be possible to determine limits for acceptable performance and possibly to monitor degradation of transducer performance over time.