Fatigue detection utilizing acoustic harmonics

摘要

Disclosed is a nondestructive test method for inspecting an object, including the steps of generating a surface acoustic wave at a first location on the object, detecting a harmonic of the generated wave at a second location on the object, and relating the characteristics of the detected wave to the remaining useful life of the object. The amplitude of the detected harmonic may be compared to standard amplitude values to predict the percentage of fatigue life remaining in the object, or the amplitude may be used to estimate the size and density of cracks in the object. Additionally, the harmonic wave may be detected for a range of stress values, the amplitude differential between the maximum harmonic amplitude and the minimum amplitude under compression calculated, and the differential related to the remaining useful life of the object.