Waveguide Transducer for Generation and Reception of High-Frequency Narrow-Beam Ultrasonic Wave

Abstract

A new type of waveguide transducer with a bidirectional-tapering structure is proposed to generate and receive high-frequency narrow-beam ultrasonic waves, which can effectively improve the defect detection resolution of high-temperature critical components in specific direction. The waveguide unit is composed of an excitation region with a tapering structure, a uniform-thickness strip region, and an incident region with a broadening structure. The tapering structure will contribute to generating the high-frequency quasi-fundamental shear horizontal (SH <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0^{\ast }$ </tex-math></inline-formula> ) wave, and the uniform-thickness strip region is conducive to transmitting SH <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0^{\ast }$ </tex-math></inline-formula> wave nondispersively, while the broadening structure can conduce to the incidence of the high-frequency narrow-beam ultrasonic wave. The critical criteria for SH <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0^{\ast }$ </tex-math></inline-formula> wave propagation with nondispersive waveform and high signal-to-noise ratio in the bidirectional-tapering waveguide are established using simulation and experiments. Moreover, the heat dissipation performance and beam radiation of the bidirectional-tapering waveguide are verified. The results show that the proposed bidirectional-tapering waveguide transducer can generate pure high-frequency narrow-beam ultrasonic wave in the high-temperature specimen.