Time-reversing Ultrasonic Transducer for Guided Wave Inspections

This work introduces a novel piezoelectric shaped transducer designed for guided wave (GW) focusing. Ultrasonic GWs, particularly Lamb waves, are widely used for the inspection of plate-like structures due to their ability to travel long distances with minimal attenuation and their sensitivity to structural defects. Unlike conventional complex phased array systems, which feature multiple piezoelectric transducers for Lamb wave focusing, this work proposes a single transducer whose piezoelectric material layout is patterned to achieve a spatial filtering effect, resulting in inherent focusing capabilities. In doing so, this work leverages the time reversal principles for the transducer’s shape design. Finite element simulations were employed to design and validate the proposed time-reversing transducer (TRT). The results demonstrate a superior focusing performance of the proposed TRT compared to a traditional array of 9 piezoelectric transducers, achieving a power efficiency nearly 64 times higher.