Sizing Small Crack-like Flaws through Non-ideal Part Surface Using Ultrasonic Measurement Model

ABSTRACT To accurately size small crack-like flaws in components with non-ideal surface conditions, such as curvature, roughness, and coating, we developed a flaw sizing method based on an ultrasonic measurement model. First, the effects of surface curvature on the sound beam profile, as well as the effects of surface coating and roughness on the wave energy are investigated theoretically and experimentally. Then, correction methods for curvature, roughness, and coating are introduced into the ultrasonic measurement model, and the flaw response in components with different surface conditions is predicted. Lastly, by accounting for the effects of surface conditions, a set of model-based flaw sizing curves is generated for predicting the equivalent size of crack-like flaws. These model-based curves can guide the setting of system parameters and improve the flaw sizing accuracy. Experiments are then conducted to verify the effectiveness of the proposed method. This work demonstrates the utility of the ultrasonic method for measuring the equivalent flaw size in practical applications.