NDE of Cylindrically Symmetric Components with Piezofilm Transducers

The flexible polymer piezofilms such as polyvinylidene fluoride[1] (PVDF) possess distinct advantages as ultrasonic transducers for inspecting cylindrically symmetric components, including rods, pipes, cladding, and tube interfaces. The flexibility and contour conforming nature of the film transducer ensure normal incidence and avoid mode conversion. In this work, PVDF transducers are used in several applications, including the evaluation of interfaces in coaxially extruded Zirconium/Zircaloy-2 tubes, the inspection of the clamping condition of Nitinol coupler and the detection of artificial flaws in Aluminum rods. Detailed description will be given for the valuation of an interface in a Zirconium/Zircaloy tube, on which the same transducer was used both as the transmitter and the receiver. The observed signals were analyzed and reflection coefficient as small as 0.006 was accurately measured. Comparison will be made with the measurement results of conventional transducers