Experimental Investigation on Dynamical Response of an Overhung Rotor due to Sudden Unbalance

Ma, Yuanyuan; Liang, Zhichao; Zhang, Dayi; Yan, Wenzhong; Hong, Jun

doi:10.1115/gt2015-42453

Cited by 12 publications

(7 citation statements)

References 4 publications

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“…Wang et al 19,20 revealed the dynamical behaviors of an overhung fan rotor with sudden unbalance by using numerical and experimental methods. Considering the effects of gyroscopic moment, Ma et al 21 simulated the vibration response of an overhung rotor excited by sudden unbalance. Sinha et al 22,23 developed a cantilevered rotor model with blades and investigated the response characteristics of the rotor system excited by sudden blade lose.…”

Section: Introductionmentioning

confidence: 99%

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

Wang

Liu

Jiang

2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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Fan blade off occurring in a running rotor of the turbofan engine dual-rotor system will cause a sudden unbalance and inertia asymmetry, which results in large impact load and consequently induces the rubbing between blade and casing. In order to reveal the transient dynamic response characteristics of actual aero-engine when fan blade off event occurs, the dynamic model of dual-rotor-blade-casing system is developed, in which the distribution characteristics of the stiffness and mass, the load transfer, and the coupling effects of dual-rotor and casing are included. Considering several excitations caused by blade off, the physical process and mechanical characteristics of the fan blade off event are described qualitatively. Considering that only the casing acceleration signal can be used for condition monitoring in actual aero-engine, the transient response including rotor vibration displacement and casing vibration acceleration during the instantaneous status are obtained. Due to the time-varying and highly nonlinear characteristics of vibration responses, frequency slice wavelet transform is employed to isolate the vibration signal features. The results show that the impact load induced by the sudden imbalance causes significant increase of vibration amplitude. The rubbing action between blade and rotor will impose constraint effects on the rotor, which decreases the transient vibration amplitude. The inertia asymmetry has a big impact on the transient response. The vibration characteristics of casing acceleration under blade off are similar to those of rotor displacement, while casing acceleration response attenuates to stable value faster and is more sensitive to high-frequency components of vibration.

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Section: Introductionmentioning

confidence: 99%

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

Wang

Liu

Jiang

2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Meanwhile, a few sudden unbalance experiments were carried out to verify the theoretical results. [11][12][13][14] Existing works demonstrated that the sudden unbalance can lead to amplification of vibration response instantaneously. The transient displacement and impact load are related to the operating state and low-order natural frequencies exist in the frequency domain.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the transient response of a speed-varying rotor with sudden unbalance and its application in the unbalance identification

Xia

Ren

Qin

et al. 2019

Journal of Low Frequency Noise, Vibration and Active Control

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It is well known that the sudden unbalance is harmful for rotor systems, since it is in huge amount and has a strong impact. Thus, it is difficult to identify the unbalance from the sudden unbalance response of rotor and very few studies have been done on this topic. This paper focuses on the transient response characteristics of the speed-varying rotor when the sudden unbalance occurs, and the inherent correlation between the unbalance and the transient characteristic quantity. First, different time-dependent functions modelling the loading process of sudden unbalance are derived and compared with the experiment results of the test rotor. The selection principles of function type and duration value are presented. Analyses of transient response characteristics are conducted over the run-up process of the rotor with different parameters of sudden unbalance. Variations of transient response characteristics are summarized into three forms. The varying laws and interrelations of characteristic quantities, and the corresponding parameter region of sudden unbalance are illustrated for each form. Based on the transient analysis results, the momentary positions and angular variations of the rotor disc at some key time instants are illustrated via introducing the key-phase signal. A novel transient-vibration-based method for unbalance identification is proposed. Only a single run-up measurement is required. Numerical experiments verify the effectiveness of the method. In summary, the proposed method can provide a new way for the unbalance identification using the transient response.

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“…Due to many factors, such as impact by birds, hail, and other foreign objects, the fan blades may be lost, causing serious accidents of the engine [2]. This engineering problem [3][4][5] is called fan-blade out (FBO) by many researchers.…”

Section: Introductionmentioning

confidence: 99%

Response of Aeroengine with Fusing Design Suffering FBO

Chen

Liu

et al. 2019

International Journal of Aerospace Engineering

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The loss of fan blades in an aeroengine, or fan-blade out (FBO), is a type of accident that causes a sudden imbalance and large impact load, which leads to complex vibration of a system. To conduct a dynamic analysis of an aeroengine rotor system is an important requirement for relevant departments. The purpose of this paper is to study the dynamic response of a complex dual-rotor system suffering FBO events and the protective effect of the fusing structure on the system. The dynamic model of an aeroengine dual-rotor system is established, and the response of the rotor system is obtained by calculation and analysis. The rear support bearing of the fan has a high reaction force, which may lead to bearing failure. The mechanism of a fusing structure is analyzed, and the results show that the sudden imbalance will produce impact loads on the rotor, resulting in a sharp increase in the vibration amplitude and reaction force, and then, attenuation to steady state. The fusing structure can reduce the amplitude of steady-state rotor vibration and reaction force on the support bearings. However, the transient response of the rotor will increase because of the sudden change in support stiffness.

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Experimental Investigation on Dynamical Response of an Overhung Rotor due to Sudden Unbalance

Cited by 12 publications

References 4 publications

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

Investigation on the transient response of a speed-varying rotor with sudden unbalance and its application in the unbalance identification

Response of Aeroengine with Fusing Design Suffering FBO

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