Characteristics analysis of magnetic memory signals for gear tooth during bending fatigue test

Metal magnetic memory (MMM) detecting technique, an alternative method for ferromagnetic components and structures failure prognostics, has attracted great attentions from many research groups. Gears endure complex stress during the meshing process. Any tiny defect in the gear tooth is likely to be the cause of great accidents after some amount of load cycles if it is not detected and treated in time. The key point of applying MMM method to gear tooth is to characterize the feature of the MMM signal during the gear damage fatigue process. In the paper, the total life bending fatigue test of a kind of spur gear is carried out with dynamic sinusoidal cycle loads. The test comes to a stop when there is obvious fatigue damage occurred. During the testing process, both the normal and tangential MMM signals along the tooth top are measured after some amount of load cycles. The characteristics of the MMM signals during the fatigue process of the gear are analyzed and features for the MMM signals are extracted, which can be beneficial to the early prognosis of the fatigue damage of spur gear tooth.