Modelling and testing of a piezoelectric sensor for defect detection in steel rods using acoustic guided waves

Abstract

Corrosion in grounding electrodes is an emerging problem affecting electric power distribution systems worldwide. An effective means to detect acute corrosion within specific grounding rods remains elusive. However, a promising method for corrosion detection is being explored that is based on acoustic guided waves. An acoustic pulse is transmitted into a steel rod using a piezoelectric element. The transmitted wave echoes off of any defects which may be present, letting their size and location be made known. A transducer is developed that best transmits the longitudinal mode into the rod. A novel model of the pulse-echo system using PSpice is presented. The model is compared with lab experiments using frequency and time domain testing and show that our model is in close agreement with the lab measurements. A novel pulse-echo transceiver embedded system is developed and presented for use in field testing. Measurements obtained from the board are compared with bench-top equipment to verify accuracy and quality.