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Research on Fatigue Crack Detection of Rail Vehicle Axle Based on Acoustic Emission

X.-J. DENG, G.-J. XUI, S.-Q. LIU

Abstract


Train axle is a key rotating part, which is related to the operation safety. It’s fatigue failure brings major hidden dangers. Monitoring and diagnosis of the axle’s state, have the great safeguard function of railway vehicle operation safety. Ultrasonic inspection and magnetic particle inspection are the usual methods, but these methods can only tell the existing cracks. They can't detect and predict the cracks' growth. Acoustic emission is an on-line technology, which can dynamic monitor the crack's initiation, growth and failure. Experiments on acoustic emission (AE) characteristics of fatigue crack in rail vehicle axles are carried out on an axle fatigue test rig. Fatigue crack AE characteristics of the rail vehicle axle include average frequency, raise time, AE hits, duration, amplitude, absolute energy. The results show that AE hits, absolute energy, average frequency can characterize the germination and extension process of fatigue crack. When there's no cracks in the axle, AE hits, absolute energy, average frequency with the cumulative time have no obvious changes; When the micro cracks occurs, AE hits rise continuously with time; When the cracks extend, the three characteristics change obviously, and the shapes are similar to the pulse. We can prevent the crack's failure and improve the train operation safety, by on-line monitoring on acoustic emission characteristics of fatigue crack.

doi: 10.12783/SHM2015/263


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