Abstract
The development of surface stress measurement technology using ultrasonic wave has been in progress. The surface tensile stress of the structure, such as nuclear power plant components, may cause stress corrosion cracking, fatigue cracking, and so on. As the sound velocity is slightly changed by the residual stress, the residual stress value is calculated from the measured sound velocities. Because the stress on the surface is important, the surface acoustic wave such as Rayleigh wave is the best choice as the ultrasonic wave mode. In the following report, the relationship of the stress value and the sound velocity is discussed based on the acoustic-elastic law of Rayleigh wave. Then the stress measurement test was performed. As a result, it is shown that the measured value by the Rayleigh wave method agrees with the measurement value by the strain gauge method within the accuracy of ±20MPa.
