Guided wave based structural health monitoring of piping systems

In the European project SAFE PIPES guided elastic waves in the frequency range between 100 and 250 kHz, generated and detected by appropriate transducer arrays, are used to monitor the structural integrity of industrial piping systems by comparing the actual state of the pipe with a predefined reference state. In the present paper, theoretical, numerical, and experimental investigations are combined to study guided wave propagation and wave interaction with relevant defects in detail. Based on these findings, a guided wave based multi-channel SHM system is designed and applied for monitoring of crack-like defects in steel pipes. The first results reveal that guided wave based SHM in the kHz frequency regime has great potential for online monitoring of piping systems. It is able to combine imaging techniques with long range detection capabilities and therefore closes the gap between high-frequency NDE on the one hand and low-frequency vibration analysis on the other hand.