Application of ultrasonic guided waves to defect inspection of large thin aluminum plate

To increase the speed of ultrasonic inspection for large thin plate, the ultrasonic guided waves and their applications to the defect inspection of large thin aluminum plate are studied. The theoretical model of guided waves propagated in large aluminum plate is presented. The wave structures of guided waves are analyzed. A method of detecting flaws in large thin aluminum plate with guided waves is designed and practiced. Experiment results indicate that the apparent reflect waves appear responding to the defect position in a 1 mm thick aluminum plate with S0 mode. The defect position can be evaluated in term of the time between the defect waves and reflect waves from plate edge. The larger the defect size is, the lager the reflect waves are. With guided wave modes sensitive to the defect, the line-scan method of guided waves is considerable in saving of testing time and the speed of ultrasonic testing for large plate can be improved effectively.