Ultrasonic inspection method for residual stress gradient distribution

The gradient distribution of the residual stress inside the component is the key factor that affects the performance of all aspects of the component. There has been a lack of effective mechanism research in the use of ultrasonic critical refracted longitudinal waves to detect the gradient residual stress. This paper studies the propagation of critically refracted longitudinal waves in solids at different frequencies, and analyzes and studies the acoustoelastic effects of critically refracted longitudinal waves from the perspective of elastic waves. Aiming at the relationship between the center frequency of LCR and its propagation depth, a mathematical model of stress gradient detection is established. The correctness of the acoustic elasticity theory and the theoretical basis of critical refraction longitudinal wave is verified by simulation. The energy depth of LCR wave propagation at different frequencies is simulated by changing the center frequency of LCR wave. The scale was verified to verify the correctness of the mathematical model of residual stress gradient detection.