This limit has to be determined experimentally for each application. The rotor shaft is supported by the main bearing fixed und the gearbox floating. Zi, Fault diagnosis of rotating machinery based on improved wavelet package transform and SVMs ensemble, Mechanical Systems and Signal Processing 21 — Once the mounting is checked, the fatigue test can start. When a surface crack is induced by fretting in a region of high cyclic strain, a growing crack can lead to a complete failure of the component. Rotating bending fatigue tests were performed using a 40mm-diameter press-fitted axle assembly. In general, multiaxial models predict the number of cycles until crack initiation and also the location and orientation of the crack.

To give an impression of the effect of fretting fatigue on the rotor shaft, a case of early shaft failure is presented. Register Already have an account? November 29, Released: Kubota, The analysis and prevention of failure in railway axles. A, Mechanics and material engineering. However, this concept and also the approach of critical bearing load, aim on excluding an initial crack respectively critical relative movements. In practice this could likely result in the need for an interference fit which would be difficult to realize.

S-N data in mid-fatigue life range and fatigue limit data of smooth small specimens are applied for material fatigue behavior. The orange line shows the superposition of both bending moments on the rotor shaft at the position of the main bearing.

Analysis of Transverse Cracks Forming in a Railway Axle

The data of real axles reveal the difference between material and a special structure. New stopping criteria for crack detection during fatigue tests of railway axles M. Another parameter has been developed by Fatemi et al. Based on the NSOFT software, the fatigue life of axles is predicted by applying appropriate fatigue life prediction methods. The rotor shaft is a highly safety relevant component of a wind turbine, since it carries the rotor of the turbine.

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Results obtained from analytical analysis could help to make a damagetolerant design, and to optimize the safety and planning of maintenance [2]. Abstract of research paper on Materials engineering, author of scientific article — Thes Rauert, Jenni Herrmann, Peter Dalhoff, Manuela Sander Abstract This paper deals with the phenomenon of fretting fatigue on the rotor shaft of a wind turbine at the tyesis fit of the main bearing.

Analysis of Transverse Cracks Forming in a Railway Axle

This one has been developed and assembled by the University of Applied Sciences in Hamburg. All railay values in the distribution are also converted to an R-ratio of -1 by considering fatigje materials sensitivity to mean stress. Wu, Study on mechanism of friction fatigue of JZ steel. Full-scale fatigue testing of wind turbine rotor shafts. New stopping criteria for crack detection during fatigue tests of railway axles HOME New stopping criteria for crack detection during fatigue tests of railway axles.

Fatigue of metals under combinations of stresses.

thesis on fretting fatigue in railway axles

Notch factor model In design guidelines like FKMthe dimensioning of certain distinguished shaft-hub connections is specified. The conditions of the tests are shown in table 3. Transferring of fatigue behavior is investigated from material to structure for Chinese railway LZ50 axle carbon steel.

New stopping criteria for crack detection during fatigue tests of railway axles

Further improvements have been made by Njinkeu and Zeise Reznicek, Fatigue tests of railway axles, Procedia Engineering 2 — The Japan Society of Mechanical Engineers. Fatigue of railway axles: After heat treatment, the microstructure is fine grain size tempered sorbite structure arilway has good plasticity and toughness, so it can meet the requirement of both high strength and high toughness for axle.

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Experiments on crack propagation and threshold at defects in press-fits of railway axles. This emphasizes, that at least in this case, fretting fatigue was more critical for the component. Especially the iterative fretting wear model seems promising, because of fatitue good accordance with the experiments. Figure 1 shows the dimensions of the axle tested. Adewusi, Wavelet analysis of vibration signals of an overhang rotor with a propagating transverse crack, Journal of Sound and Vibration 5 — This seems reasonable when considering that cracks from fretting fatigue will at a certain length start growing under Mode I, dominated by the principle stress, in a direction perpendicular to the contact surface.

The main bearing of such an arrangement is typically a spherical roller bearing and the gearbox is elastically mounted.

Zhu, Research progress in mechanism and protection methods of material fretting fatigue. This means that typically the bending moment at the rotor shaft resulting from the aerodynamic loads will reduce the bending moment resulting from the own weight of the rotor. And SEM was used to observe and analyze the fracture.

VDI Verlag, 21 – In the case of the rotor shaft, the principle stress is set equal to the bending stress. The objective of these approaches is that a crack initiates in a plane of maximum strain.

thesis on fretting fatigue in railway axles

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