Effect of a transverse crack on the dynamic behaviours of a 3D rod-fastening rotor bearing system

Wang, Nanshan; Liu, Heng; Liang, Yi; Wang, Qidan; Qi, Shengwen; Xu, Zhicheng

doi:10.1108/ilt-05-2020-0189

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…Li et al [27] studied the nonlinear dynamic characteristics of a three-disk bending torsional coupling rod fastening rotor under rub impact fault, concluded that the influence of torsional vibration on bending vibration gradually increases with the increase in rotating speed. Wang et al [28,29] studied the dynamic characteristics of rod fastening rotor under the coupling fault state, which are the non-uniform contact stressors of the disks, crack, initial bending and others, and carried out experimental verification. Hei et al [30,31] studied the nonlinear dynamic characteristics of coupling faults, which are the rod fastening rotor with looseness of support and rub impact.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamic Characteristics of Rod Fastening Rotor with Preload Relaxation

Li¹,

Zhang²,

Shen³

et al. 2022

Energies

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Compared to ordinary rotor, rod fastening rotor has the advantages of lighter weight, higher strength and easier installation, so it is widely used in gas turbine. However, in the process of a long-term operation, the rod may be deformed due to the influence of alternating load, high temperature and other uncertain factors. In serious cases, it can even lead to a major accident. The discontinuous characteristic of rod fastening rotor leads to great differences in dynamic characteristics compared to ordinary rotor. Based on the Herz contact theory and GW contact model, the contact effect between two discs was studied, and the relationship among the contact load, the distance between two disks and the equivalent bending stiffness was obtained. Findings show the bending stiffness to decrease nonlinearly with the decrease in contact load. The lumped mass method was used to establish the rotor model. The contact effect was considered and the Runge–Kutta method was used to solve the model. Combined with the bifurcation diagram, time domain diagram and spectrum diagram, the influence of contact stiffness on rotor dynamic characteristics was analyzed. The results show that the dynamic characteristics of the rod fastening rotor are rich due to the influence of nonlinear factors. In the case of uniform relaxation, the contact stiffness has different effects on the response state and frequency doubling amplitude of the system at different speeds, which is mainly related to the motion state of the system. In the case of non-uniform relaxation, the degree of relaxation does not affect the motion state of the system, but only changes the amplitude of vibration. The results provide theoretical support for condition monitoring and fault diagnosis of rod fastening rotor.

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Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamic Characteristics of Rod Fastening Rotor with Preload Relaxation

Li¹,

Zhang²,

Shen³

et al. 2022

Energies

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show abstract

“…e results show that the greater the rotating speed, the greater the influence of rub impact force on the rotor. Wang et al [14,15] studied the influence of coupling faults such as uneven contact stress distribution between two disk and initial bending of the system due to the existence of cracks on rotor dynamic characteristics and verified it through experiment. Cui et al [16] used finite element method to study the dynamic characteristics of rod fastening rotor under different preload and bearing assembly clearance.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamic Characteristics of Multidisk Rod Fastening Rotor with Axial Unbalance Mass Distribution

Zhao

Zhang

Liu

et al. 2022

Shock and Vibration

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During long-term operation, the blades of rod fastening rotor are very prone to fault and may cause uneven axial mass distribution. The dynamic characteristics of a multidisk rod fastening rotor with axial unbalance mass distribution are studied. A four-disk rod fastening rotor model was established by the lumped mass method. The mass unbalance on different disks was used to simulate blade faults in different parts, and nonlinear factors such as oil film force and disk contact effect were considered. The fourth-order Runge-Kutta method was used to solve the model, and the spectrum and axis trajectory curves were obtained. The influence of fault location and rotating speed on rotor dynamic characteristics was analysed when there were blade faults on two disks. The results show that a large, unbalanced mass will bring strong nonlinear characteristics. The rod fastening rotor may be in different motion states at different rotating speeds. When the fault position of two disks changes, the changes of bearing spectrum, axis trajectory, and phase difference have regularity. The results can provide a theoretical basis for condition monitoring and fault diagnosis of rod fastening rotor.

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Multi-optimization of rod fastened rotor on the distribution of bending stiffness and unbalance

2024

AIP Advances

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A rod fastened rotor (RFR), which contains serial disks, rods (or a rod), and a torque tube, is the main form of heavy duty gas turbines and light duty aero engines. The roughness of the interface is the main parameter affecting the bending stiffness of RFR, and the jumpiness of the disks is the intuitive representation of the unbalance of the rotor. In this paper, a multi-optimization algorithm, NSGA-Ⅱ, was used to improve the vibration behavior of the RFR-bearing system. First, the quantitative relation between the bending stiffness of the rotor and the roughness of the interface was set up by combining the Persson contact theory and the Greenwood–Williamson model, and the nondimensional bending stiffness (NS) was proposed as the optimization objective of roughness. Then, the optimization objective of the jumpiness of the disk, (A + B), was rendered based on the minimum unbalance force. Finally, the multi-optimization on the roughness and jumpiness of the RFR was carried out, and the vibration behavior was improved greatly. In addition, this multi-optimization method was applied to a practical RFR, and the experimental results showed that the vibration amplitude was reduced by about 82%. The work in this paper can provide the guidance for vibration reduction of the rotor system.

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Effect of a transverse crack on the dynamic behaviours of a 3D rod-fastening rotor bearing system

Cited by 3 publications

References 15 publications

Nonlinear Dynamic Characteristics of Rod Fastening Rotor with Preload Relaxation

Nonlinear Dynamic Characteristics of Rod Fastening Rotor with Preload Relaxation

Nonlinear Dynamic Characteristics of Multidisk Rod Fastening Rotor with Axial Unbalance Mass Distribution

Multi-optimization of rod fastened rotor on the distribution of bending stiffness and unbalance

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