Development of a Multichannel Piezoelectric Ultrasonic Transducer Array for Nondestructive Testing Applications

Welded structures have been widely used in automotive production, aerospace, construction industry and other fields. With the trend of industrial welded structures becoming larger and thicker, it is of very importance to test the weld quality of the medium-thickness steel plates above 25 mm for ensuring the safety and reliability of the weld structures. In this paper, a multi-channel piezoelectric ultrasonic transducer array has been developed for detecting the sub-millimeter defects inside medium-thickness steel plates. Both the electrical impedance analysis and ultrasonic pulse echo test characterization show that the theoretical design model can effectively guide the design of the ultrasonic transducer array design. Besides, a standard butt-welded steel plate was tested for weld defects with a minimum feature size of 0.5 mm, and the results show that the developed multi-channel piezoelectric ultrasonic transducer array can accurately detect sub-millimeter weld defects, with a detection resolution of better than 0.5mm.