Device and method for detecting and positioning foaming defects of metal material sandwich foaming plate

The invention discloses a device and a method for detecting and positioning foaming defects of a metal material sandwich foaming plate. The detecting and positioning device comprises an ultrasonic guided wave exciting and receiving device, an ultrasonic guided wave detecting probe and a motor direct-driven XY cross-shaped double-axis motion platform, the ultrasonic guided-wave detection probe comprises an excitation probe and four ultrasonic guided-wave receiving probes, and is used for scanning the outer surface of the detected piece in the transverse and longitudinal directions, and scanning the outer surface of the detected piece according to a distance and amplitude change curve of an ultrasonic guided-wave A scanning receiving signal; and determining the position of the foaming defect of the detected piece by comparing the change rates of the detection amplitude curve and the fitting amplitude curve. According to the technical scheme, the position of the invisible defect can be accurately positioned, irr