Finite element based stability analysis of a rotor-bearing system having a functionally graded shaft with transverse breathing cracks

Gayen, Debabrata; Tiwari, Rajiv; Chakraborty, Debabrata

doi:10.1016/j.ijmecsci.2019.04.056

Cited by 28 publications

(5 citation statements)

References 41 publications

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“…As ∆ϕ ∈ [0, θ 1 ], the crack is fully open and the moment of inertia of closed portion can be obtained from Refs. [5,22] as…”

Section: Stability and Improved Breathing Functionmentioning

confidence: 99%

“…Subsequently, many breathing functions dominated by different dynamic loadings are continuously developed due to different types of cracked rotors or operating conditions [19,20]. In order to obtain a more accurate time-varying stiffness, the stress intensity factors and strain energy density are employed to determine crack state and neutral axis [21,22]. Rubio proposed a method based on the stress intensity factor of an open crack with sickle shape to determine the relative depth and front position of the crack [23].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Vibration and Stability Analysis of a Bearing–Rotor System with Transverse Breathing Crack and Initial Bending

Wang

Xiong

2021

Machines

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This paper focuses on the stability and nonlinear response of a bearing-rotor system affected by a transverse crack and initial bending which was thought to be part of an unbalance or had been neglected before. The differences of breathing functions for the transverse breathing crack caused by initial bending is presented here, and the calculation of time-varying finite elements stiffness matrix of the cracked shaft is improved by replacing traditional the approximate crack segment with an exact area. After establishing the dynamic model of the cracked rotor with initial bending, vibrational characteristics such as amplitude-speed diagram, frequency spectrogram and bifurcations are investigated in detail. The eigenvalues of the transition matrix are calculated and analyzed as an indicator of dynamic stability with the growths of crack depth and initial bending. Many differences are found between the two cases of dynamic response of rotor system by numerical simulation. The frequency change with the growth of initial bending is opposite to the change with the growth of crack depth, and the shapes of amplitude-speed also having great different features. Stable regions are reduced and extended laterally by initial bending. All these results obtained in this paper will contribute to identify the bending fault and assess the stability of the bearing-rotor systems.

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“…As ∆ϕ ∈ [0, θ 1 ], the crack is fully open and the moment of inertia of closed portion can be obtained from Refs. [5,22] as…”

Section: Stability and Improved Breathing Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Vibration and Stability Analysis of a Bearing–Rotor System with Transverse Breathing Crack and Initial Bending

Wang

Xiong

2021

Machines

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“…In a 3‐D FE model with a fixed end boundary condition, a straight front crack and its breathing represented by the local flexibilities was also studied 25,26 . Recently, finite element analyses were carried out to analysis stability 27 and whirl frequencies and critical speeds 28 of a rotor‐bearing system, and analysis free vibration of functionally graded shaft system with a surface crack 29 and multiple cracks 30 …”

Section: Introductionmentioning

confidence: 99%

Location dependence of breathing mechanism for a slant crack in a shaft

Mobarak

Yang

2020

Fatigue Fract Eng Mat Struct

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Periodic stresses are always imposed on a rotor, and thus, a crack due to fatigue is unavoidable. Machinery must be properly diagnosed to avoid tragic accidents. Vibration detection is the most important tool for such a diagnosis system. It is important to know the vibration characteristics of a cracked rotor in order to develop a monitoring system which can detect a crack in an early stage of propagation. In this study, to explore the crack breathing mechanism, a three-dimensional finite element model is simulated by using a commercial analysis solver-Abaqus/Standard. A two-disc rotor system with a slant crack is used under the coupling effect of rotor weight and unbalance force. Unlike crack breathing under rotor weight-only, a crack opens and closes differently under the effects of unbalance forces. Crack breathing depends on its location along the length of the shaft and individual parameters of the rotor system. A few crack locations are recognised along shaft length where the crack may stay fully closed or open during shaft rotation under certain loading circumstances. These locations also split the shaft into different areas based on the orientation of the unbalance force, crack size and location, where shaft stiffness may be higher or lower. Presented findings indicate that predicting the dynamic response of cracked rotors can be anticipated much accurately. Therefore, the impacts of unbalance forces and individual rotor physical characteristics on crack breathing must be taking into consideration.

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“…As the crack damage is hard to detect in the early stage, it has become severe threats to the operation safety of equipment and attracts the attentions of many researchers. In order to develop effective techniques for detecting the crack damages, a large number of investigations have been published to analyze the nonlinear dynamics of cracked rotors and to gain insights into the dynamic response characteristics [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

The Vibration of a Transversely Cracked Rotor Supported by Anisotropic Journal Bearings with Speed-Dependent Characteristic

et al. 2020

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This paper presents the vibration of a transversely cracked rotor supported by anisotropic journal bearings, where the speed-dependent characteristic of bearing is considered. A 3D finite element model and the contact-based approach are employed for the shaft and crack. The governing differential equations of the whole cracked rotor-bearing system were obtained by synthesizing the equations of the cracked shaft, the breathing crack and the journal bearings. In order to solve the computational difficulties caused by the high dimensions of model, the free-interface complex component mode synthesis method (CMS) is employed to reduce the order of the model. On this basis, the eigenvalue and the steady-state forced response of the cracked rotor-bearing system are obtained by the Hill’s method. Finally, the effects of the anisotropic and speed-dependent characteristics of bearings on the vibration of the system are studied. Numerical results show that both the two characteristics can significantly affect the response of the system. The anisotropy in the bearing leads to the split of resonant peaks and influence the amplitudes of the peaks. The speed-dependent characteristic mainly affects the responses at the speeds close to the resonant regions, because the parametric excitation effect of the resonance region is greater than other speeds.

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Finite element based stability analysis of a rotor-bearing system having a functionally graded shaft with transverse breathing cracks

Cited by 28 publications

References 41 publications

Vibration and Stability Analysis of a Bearing–Rotor System with Transverse Breathing Crack and Initial Bending

Vibration and Stability Analysis of a Bearing–Rotor System with Transverse Breathing Crack and Initial Bending

Location dependence of breathing mechanism for a slant crack in a shaft

The Vibration of a Transversely Cracked Rotor Supported by Anisotropic Journal Bearings with Speed-Dependent Characteristic

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