Defect Localization Using Flexible Omni-Directional Interdigital Ultrasonic Transducers

Interdigital ultrasonic transducers (IDTs) hold great promise for non-destructive testing (NDT) due to their tunable frequency and beam-focusing capabilities. Conventional IDTs are often constrained by narrow scanning angles and relatively low spatial utilization efficiency, which hinders the balance between real-time monitoring and detection performance. To address these limitations, we propose a flexible omnidirectional interdigital ultrasonic transducer (ODIDT) featuring a sector-shaped interdigital structure. This design not only enables directional excitation of ultrasonic waves but also enhances their propagation efficiency. While sector-shaped interdigital transducers have seen limited exploration in NDT, this work introduces a novel sector-based defect localization method that leverages the ODIDT’s directional transmission and reception capabilities. The approach allows for efficient sector scanning and precise defect localization. Experimental results at a center frequency of 380 kHz demonstrate that the proposed ODIDT can accurately locate defects of varying sizes and positions on an aluminum plate.