Paper Title:

An Experimental Study of Breathing Mechanism for the Transversely Cracked Shafts

Periodical Advanced Materials Research (Volume 338)
Main Theme Product Design and Manufacturing
Edited by Xiaodong Zhang, Zhijiu Ai, Prasad Yarlagadda and Yun-Hae Kim
Pages 547-552
DOI 10.4028/www.scientific.net/AMR.338.547
Citation He Len Wu et al., 2011, Advanced Materials Research, 338, 547
Online since September, 2011
Authors He Len Wu, Zhong Yi Cai, Ke Qin Xiao
Keywords Breathing Mechanism, Shaft Crack, Stiffness, Vibration
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Abstract

Shaft fatigue crack is one of the most common defects in rotating equipment, due to its extensive operation with continuous heavy loads. Finding an efficient way to evaluate the true stiffness variation due to the crack rotation is the key step to develop both on-line and off-line crack diagnostic techniques. This study analyzed time-variant bending stiffness of elastic shafts with experimentally-induced fatigue, welding and wire cut transverse cracks. It was found that crack gap has a significant effect on the opening and closing behaviour of the transverse crack. As in the case of a cut crack, large crack gap could completely prevent the crack from closing during rotation. A fatigue crack without a clear gap shows a typical opening and closing behavior. Further, it remains fully closed within a small angular range and most of time it is partially closed. It was also observed that both switch and harmonic models cannot describe periodic stiffness variation well enough to represent the actual breathing function of the fatigue crack.