Numerical Investigation of Influence of Temperature on Propagation of Ultrasonic Waves in Waveguides with Mode Conversion

Abstract

Abstract-In the case of the objects with a high temperature the measurements are often performed using waveguides in order to protect the ultrasonic piezoelectric transducers from a high temperature. In some cases, for measurement of specific properties of materials, shear waves are used. Shear waves can be generated exploiting mode conversion phenomenon using a longitudinal wave transducer and a waveguide with deflected front surface. However, the deflection angle has to be carefully selected, when it is required that the shear waves would propagate parallel to the waveguide axis. The proper deflection angle depends on material used for the waveguide properties. When the temperature changes, the properties of the material (as ultrasonic velocity) change as well, causing the change of the reflection angle and the propagation path. A numerical investigation was performed in order to evaluate how the change of the temperature will influence the reflection angle of the ultrasonic waves and the propagation path. It is shown that the change of the temperature influences the reflection angle and propagation path of ultrasonic waves and should be taken into account.

High Temperature Ultrasonic Transducers: A Review

“…Using such transducers dependences of the ultrasound velocity in the Pb/Bi alloy versus temperature in the range from 160 °C to 460 °C for the first time were measured [ 50 ]. Influence of trailing waves was reduced by applying not tapered but cylindrical threaded rods with grooves made on an outer surface of the rod ( Figure 5 ) [ 51 ].…”

“…An advantage of the latter design is that for excitation of the shear wave a conventional longitudinal mode transducer can be used. Influence of temperature gradients on propagation of longitudinal and shear waves in the buffer rods was analyzed by us in [ 51 ].…”