Modeling of Multi-stepped Rotor-bearing Systems by the Continuous Segment Method

Mereles, Arthur; Cavalca, Kátia Lucchesi

doi:10.1016/j.apm.2021.03.001

Cited by 16 publications

(12 citation statements)

References 40 publications

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“…With the particularity and complexity of the objects, more and more modeling methods for specific objects have been researched and developed. Filsoof et al [15] proposed a novel method and system modal dynamic modeling method for multirotor wind turbines; Mereles [16] proposed a method based on distributed parameters or continuous models; these proposed methods can be applied to complex rotor systems with multistep sections and multidisks and multibearings. In order to solve specific eigenvalues, some scholars have proposed a new method for modeling complex rotor systems with multiple discs and multiple bearingscontinuous segmentation method [17].…”

Section: Introductionmentioning

confidence: 99%

Vortex Trajectory of Rotating Shaft Undergoing Vibration Coupling of Parallel Multicylinders

Zhang

Tang

et al. 2022

Advances in Materials Science and Engineering

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Multiple threshing cylinders of combine harvester are mainly driven in parallel, whose transmission methods are complex causing the excitations coupled with each other. The mutual excitation coupling of multiple threshing cylinders causes a severe vibration state of the combine harvester with poor stability. In order to analyze the influence of transmission system coupling on the unbalanced response of the parallel multicylinder system, this paper established a mathematical model of the parallel multicylinder system and derived the general vortex trajectory expression of the unbalanced response of threshing cylinder shaft undergoing vibration coupling of parallel multicylinders. Vibration tests of the bearing seat and the rotating shaft were carried out for comparison and verification. Results showed that the existence of the transmission chain and the transmission mode cause the boundary conditions of the multicylinder system to change, which ultimately led to changes in the unbalanced response of the transmission system. The contribution rate of different transmission methods and rotation speeds to the vibration amount at the fundamental frequency of the multicylinder was 5% to 30%. The existence of the transmission system caused the vibrations of the various units to be coupled with each other, mutually transmitted, and superimposed, leading to changes in the vortex shape of the rotating shaft and the unbalanced response of the transmission system.

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Section: Introductionmentioning

confidence: 99%

Vortex Trajectory of Rotating Shaft Undergoing Vibration Coupling of Parallel Multicylinders

Zhang

Tang

et al. 2022

Advances in Materials Science and Engineering

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“…is change is not properly described in the mathematical model of beam theories. Some scholars considered this influence and modified modal analysis model to reckon it in [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…e free vibration analysis of multiple-stepped beams was conducted by the discrete singular convolution method and the Adomian decomposition method, respectively [19,20]. e multistepped rotor systems were analyzed using a new method called continuous segment method [21]. All this literature solves the dynamic analysis of the stepped rotor by the numerical methods.…”

Section: Introductionmentioning

confidence: 99%

A Modified Transfer Matrix Method for Modal Analysis of Stepped Rotor Assembly Applied in the Turbomolecular Pump

Zhang

Tang

Tong

2022

Shock and Vibration

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An accurate modal analysis of the stepped rotor assembly is significant in the design process of rotors. The transfer matrix method (TMM) is widely used in the modal analysis of the rotor. However, the influences of the step and the assembling modes are not considered in the traditional TMM. In this paper, a modified transfer matrix method is presented for the modal calculation of the rotor in the turbomolecular pump. The stiffness reduction of stepped segments and the effect of assembled components are considered in this modified method. First of all, the traditional transfer matrix model is built. Then, the stepped segments of the rotor are changed into conical segments and the lumped mass model of conical segments is calculated. Next, the conicities of conical segments are analyzed and relations between conicities and dimensions of the rotor are discovered. Finally, the stiffness factors which can describe the effects of different assembling modes are introduced and optimized. The optimized stiffness factors are analyzed and explained from the perspective of contact stress. The modal of the stepped rotor assembly could be computed with high accuracy by using this method.

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“…The low torsional stiffness of the rotor attachment point will affect the first flapwise backward whirling mode by reducing the corresponding natural frequency. Mereles et al [7] proposed a new method here named Continuous Segment Method (CSM) for modeling complex rotor systems with multiple disks and bearings, changing some parameters of the system, and calculating by CSM method and finite element method. The results show that the results of the higher-order modes of the two methods are equivalent when the finite element mesh is sufficiently discrete.…”

Section: Introductionmentioning

confidence: 99%

Critical speed analysis of the shafting rotor of the vertical long shaft fire pump under the different positions of the impellers

Yang

Jin

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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For multi-stage pumps, the change of the impeller stage spacing will have a greater impact on the dynamic characteristics of the shafting rotor. The paper took XBC18-178-240LC3 vertical long shaft fire pump as the research object, using ANSYS Workbench software to study the relationship between the critical speed of the shafting rotor and the different positions of the impellers. First, 9 shafting rotors (based Z4,Z5 and Z6 models) under the different positions of the impellers were established; and then the change law of the critical speed on 9 shafting rotors in the first 12 modes was studied. The results showed that different positions of the impeller on the shaft have a great impact on critical speed of the shafting rotor. With the increase of the distance between the impeller stages, the low-order critical speed (6th order and within) of the Z4 model shafting rotor decreases. However, the low-order critical speed (5th order and within) of the Z5 and Z6 model shafting rotors decreases with the increase of the distance between the impeller stages, and the high-order critical speed doesn’t satisfy this law. Considering static characteristics of the shafting rotor and actual engineering applications, the paper selected the Z5-stage spacing 800mm shafting rotor model as the best case, providing a theoretical support for the subsequent vertical long shaft fire pump design optimization.

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Modeling of Multi-stepped Rotor-bearing Systems by the Continuous Segment Method

Cited by 16 publications

References 40 publications

Vortex Trajectory of Rotating Shaft Undergoing Vibration Coupling of Parallel Multicylinders

Vortex Trajectory of Rotating Shaft Undergoing Vibration Coupling of Parallel Multicylinders

A Modified Transfer Matrix Method for Modal Analysis of Stepped Rotor Assembly Applied in the Turbomolecular Pump

Critical speed analysis of the shafting rotor of the vertical long shaft fire pump under the different positions of the impellers

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