Reliability evaluation of PECT-EMAT integration nondestructive testing method

Metal structures are widely used in modern industrial fields, in which various defects are probably generated from manufacture to service. Specifically, both the surface and bottom of structures may emerge defects. Under such complex conditions, a single non-destructive testing (NDT) method commonly fails to satisfy all needs. However, two or more targeted NDT methods present low efficiency and high cost. Thus, a novel pulsed eddy current and electromagnetic ultrasonic (PECT-EMAT) integration testing method was developed and verified for composite defects detection by simulations and experiments in this study, contributing to significantly simplifying the testing systems and improving the testing efficiency. Meanwhile, the detection capability of the PECT-EMAT integration testing method was evaluated by developing a reliability evaluation method through probability of detection (POD). Specifically, a theoretical model of POD was established according to the principle of probability and statistics. Then, the signal characteristic database of composite defects was built following the integration testing method, and the signal statistical analysis was performed. Finally, the POD analysis of composite defects detection was conducted through simulations and experiments. Furthermore, the detectability of the PECT-EMAT integration testing method and the reliability of the composite defect detection were investigated, and the minimum detectable size of the composite defect detection was determined.