Relationship between Stress and Temperature Dependence of Ultrasonic Shear Velocity

Abstract

The effects of applied elastic stress on the temperature dependence of 10 MHz ultrasonic shear velocity have been studied in A533B steel. The measurements were performed with stress perpendicular to the propagation direction of ultrasonic shear waves. The polarization direction was either parallel to or perpendicular to that of stress. In all these measurements, the ultrasonic velocity is found to decrease linearly with temperature, and the slopes of the lines of best fit of ultrasonic velocity versus temperaturevary considerably when the specimen is subjected to stress. The results obtained when the stress is applied in a direction perpendicular to ultrasonic propagation and parallel to polarization show that the temperature dependence of ultrasonic shear velocity increases linearly with applied tensile stress, and decreases when the stress is compressive. When the stress is applied in a direction perpendicular to both propagation and polarization, the temperature dependence decreases linearly with applied tensile stress and increases with compressive stress. Calibration curves relating relative changes in the temperature dependence of ultrasonic velocity to applied stress in A533B steel are constructed. Using these curves, the sensitivity in determining unknown applied stress in steel is estimated to be ±32 MPa, when the stress is parallel to polarization and ±35 MPa when the stress is applied perpendicular to polarization.