Unstable Vibrations of an Unsymmetrical Shaft Supported by a Flexible Base near the Major Critical Speed.

2013

JSDD

The studies of the cracked rotor demonstrated by Japanese researchers started in early 1980s and many papers have been reported. The characteristics of these Japanese papers are: A group of papers investigated the vibration of the practical machinery and the estimation of the position and depth of the crack was tried in the quite early time, Another group of papers used a simple rotor model and investigated the vibration caused by the crack theoretically considering the nonlinearity involved in the crack's characteristic. In the following, these studies of the cracked rotor are divided in the groups, the studies on the vibration analysis of the cracked rotor using simple rotor model, the studies on the vibration analysis of the rotor system with the breathing crack, the studies on the modeling and detection method of the crack and case study of the cracked rotor, and reviewed in detail.

“…Resonance curve of the cracked rotor (4) Fig. 10 Theoretical model (5) Fig. 11 Natural frequency and unstable ranges (5) shown in Fig.…”

Section: Figmentioning

confidence: 99%

“…9) were analyzed, and the experimental results were explained. Ikeda et al (5) investigated the vibration characteristics of the asymmetric shaft system. The asymmetric rotating shaft is not the cracked rotor, but it shows the same characteristics of the rotor system with an open crack.…”

Section: Figmentioning

confidence: 99%

Review of Research on the Cracked Rotor in Japan

2013

JSDD

Vibrations of an Asymmetrical Shaft With Gravity and Nonlinear Spring Characteristics (Isolated Resonances and Internal Resonances)

Ishida

Liu

Journal of Vibration and Acoustics

et al. 2008

An asymmetrical shaft supported by single-row deep groove ball bearings with clearance has nonlinear spring characteristics, rotating stiffness difference in shaft, and static stiffness difference in support at the shaft ends. When an asymmetrical rotor is supported horizontally, a harmonic excitation due to the unbalance and a double frequency excitation due to the coexistence of gravity and shaft asymmetry work simultaneously. As a result, this system becomes a nonlinear parametrically excited system with multiple periodic excitation forces. In this paper, nonlinear forced vibrations and parametrically excited vibrations are investigated theoretically and experimentally. Vibration characteristics of both isolated resonances and internal resonances are studied.

Finite Element Analysis and Experimental Validation of Transfer Function of Rotating Shaft System With Both an Open Crack and Anisotropic Support Stiffness

Yao

Journal of Vibration and Acoustics

Yabui

2018

In this paper, transfer function of rotating shaft system for detecting transverse open crack is developed. Rotating shaft system is modeled using one-dimensional finite element method (1D-FEM), and quantitative analysis is performed. Open crack is modeled as weak asymmetry rotating with shaft's rotation. It is known that, when both open crack and support stiffness anisotropy coexist, various frequency components of shaft's vibration are generated through their successive interaction. This paper evaluates the order of these components, and concludes that first five main components are enough to investigate interaction of open crack and support stiffness anisotropy. Then, five sets of transfer functions for these components are derived. The validity of this set of transfer functions is confirmed by numerical simulation. Moreover, excitation experiment utilizing active magnetic bearing (AMB) is performed, and the validity of derived transfer function was verified experimentally.