Ultrasonic penetration method for weld root crack in orthotropic steel decks: differentiation and quantitative recognition

Weld root crack represents a significant concern in terms of fatigue on orthotropic steel decks (OSDs). This study presents a crack detection method based on ultrasonic penetration signals, to effectively distinguish and quantify cracks in decks. Firstly, based on the principles of sound diffusion and the structural characteristics of OSDs, the parameters were established. Then, the propagation mechanism of ultrasonic waves in decks containing cracks was investigated by finite element analysis. The variations in received signal intensity caused by root-deck and root-weld crack parameters were analyzed and the methods for distinguishing between crack types and determining characteristics were proposed. Finally, experimental tests were conducted on weld root cracks to validate the feasibility of the detection method. The research findings demonstrate that the selected detection parameters adequately meet the requirements for crack detection. By utilizing fitting functions between the transmission signals from two sets of detection parameters and the projected crack length, the method achieves accurate identification of crack length and angle, with an error rate of less than 10%.