Design and experiment of high temperature wedges for shear horizontal plate acoustic waves

Theoretical and experimental studies of ultrasonic wedges which can generate and receive shear horizontal (SH) plate acoustic waves (PAWs) in a metal plate at temperatures up to 200°C are presented. Brass which has a slow shear (S) wave velocity was chosen as the high temperature wedge material. Mode conversion method is used to convert longitudinal (L) waves generated by a high temperature integrated ultrasonic transducer to S waves in the brass wedge. The calculated L to S wave mode energy conversion efficiency is 79.7% with a conversion angle of 64.1°. The S waves in the wedge glued onto a stainless steel (SS) plate with a wedge angle of 42.9° have been converted to SH PAWs in the SS plate. Analytical analysis of the coupling coefficient from the S waves in the wedge to the SH PAWs in the plate is presented. Measurement results demonstrated that SH PAWs using such wedges may be a practical approach for non-destructive testing and structural health monitoring of metal structures.