Plane stress measurement on the cross-section of steel components using ultrasonic shear waves

Plane stress measurement is an important means to obtain the mechanical information of structural steel components. Traditional structural health monitoring techniques are difficult to perform non-destructive measurement of internal plane stress of the components. In this study, we theoretically and experimentally proposed a method for measuring average plane stress on the cross-section of steel components. We derived a new form of plane stress-acoustic relation based on shear wave birefringence and successfully achieved plane stress separation. The phase difference of two groups of echoes was used to calculate effective phase velocity information, where Fourier-transform was used for obtaining the echo phase spectra. The experimental calibration for determining the values of five stress coefficients was presented and the optimal frequency was found to be the center frequency of the probe. The strain gauge method was adopted to prove the effectiveness of the proposed method, and good experimental results were observed.