Torsional ultrasonic guided wave-based smart SHM system for locating defects in pipes

Structural health monitoring (SHM) of pipelines using ultrasonic guided waves (GW) is highly suitable for long-range and real-time monitoring. Most such demonstrations utilize bulky piezoelectric transducer rings and laboratory-grade ultrasonic NDT equipment to monitor pipelines and are therefore difficult to translate from laboratory to on-field deployable systems for real-time monitoring of state-of-health of pipelines. In this work, we have demonstrated a novel damage identification and localization algorithm for pipes, realized with a compact FPGA-based smart GW-SHM system. The custom-developed board with Xilinx Artix®-7 FPGA (Digilent Cmod A7) and frontend electronics is capable of actuating the PZT thickness shear transducers, data acquisition and recording from PZT sensors. The algorithm is a variation of the common source algorithm, adapted for cylindrical geometry, and is applied to detect location of mass loading on a steel pipe. The experimental results were verified with finite element method (FEM) simulations.