Research on electromagnetic ultrasonic and eddy current composite detection method for cracks in aircraft aluminum alloy plates

Purpose Aircraft aluminum alloy plates can develop a large number of cracks during long-term service and require rapid detection. This study aims to develop a fast and effective detection method based on electromagnetic acoustic transducer and pulsed eddy current testing. Design/methodology/approach This paper proposed a composite detection method of electromagnetic ultrasonic guided waves and eddy currents combined with electromagnetic ultrasonic body waves for aircraft aluminum alloy plates, and conducted a composite detection test study on cracks in aluminum alloy plates. The rapid detection capability of electromagnetic ultrasonic guided waves was analyzed, the influence of key parameters in the composite method was discussed, and the effectiveness of surface and internal crack detection was evaluated. Findings Research showed that this method reduced the effective detection area of surface cracks, improved detection efficiency, and achieved comprehensive and efficient detection of surface and internal cracks. When the angle between the probe and the crack was 90°, the echo amplitude of the surface defect was the largest. Changes in the lift-off value and crack characteristics significantly affected the intensity and quality of the detection signal. The planar four channel eddy current detection probes had good applicability to cracks on aluminum alloy plates. Originality/value This research has provided an effective method for efficient and accurate detection of defects in aircraft aluminum alloy plates.