| The flaw detection methods of roll fatigue layer mainly are magnetic particle inspection, penetration testing, eddy current inspection and ultrasonic flaw detection. However, Existing methods have many limitations. For example, Magnetic powder flaw detection can only be used on the ferromagnetic material. Penetration inspection can only be used to detect the roll surface crack. Eddy current inspection can only be used on the conductor material and so on. In contrast, the study of ultrasonic nondestructive testing has practical value.In this paper, use the methods of theoretical analysis, simulated analysis and experimental analysis to give the following work.(1) Based on the ultrasonic guided wave theory, analyze the effect of guided wave propagation when the roll fatigue layer thickness or the degree of fatigue or the radius are changed. Do the experiment in the form of transmission and collect the data.(2)Ues the merhods of fourier spectrum analysis and time-frequency analysis to process the data. Get some lows about the spectrum shift. And researches show that the time-frequency method is more reasonable. |
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