Comparison of Acoustoelastic Methods to Evaluate Stresses in Steel Plates and Bars

Abstract

Most of the methods for determining residual stresses inside metallic solids are destructive, which is undesirable. The ultrasonic technique provides a useful nondestructive tool in the evaluation of stresses. This work presents the application of shear and longitudinal waves in the determination of stress state in a steel bar. A bar stressed by a hydraulic system is used to simulate the effect of the tensile stress. The stresses are recorded and compared with the real value calculated using the force and the bar cross-sectional area. The comparison between the theoretical and experimental results shows that it is possible to correlate tensile stresses and velocity with both methods, although the longitudinal critically refracted (LCR) waves have greater sensitivity to the stress.