In this paper,a metal edge thickness detection method is optimized to place the electromagnetic ultrasonic transducer(EMAT)at the specimen edge to stimulate the shear wave and Rayleigh wave and improve the accuracy of the specimen thickness detection.First,a finite element model is established to simulate the propagation process of shear wave and Rayleigh wave in metal and the first echo voltage signal amplitude.Then,the first echo voltage signal is phase-analyzed by the superheterodyne orthogonal phase-sensitive detection system.Finally,in order to verify the feasibility of the edge detection method,a series of experiments were done for noise reduction according to the experimental echo signal,compared with the theoretical thickness value.The results show that the optimized edge detection method can improve the accuracy of the specimen thickness detection,and the resolution of the specimen with small thickness change is high,which is better than the traditional jet difference thickness measurement technique.
edge detectionsuperheterodyne phase sensitive detectionelectromagnetic ultrasonic transducerfinite element analysis
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