scholarly journals Dynamic Behaviour Analysis of Turbocharger Rotor-Shaft System in Thermal Environment Based on Finite Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhihao Liu ◽  
Renren Wang ◽  
Fang Cao ◽  
Pidong Shi
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Tangential Force ◽  
Accurate Prediction ◽  
Internal Damping ◽  
Rotor Shaft ◽  
Shaft System ◽  
Rotor Bearing ◽  
Rotor Dynamic ◽  
Bearing System

The stable operation of a high-speed rotating rotor-bearing system is dependent on the internal damping of its materials. In this study, the dynamic behaviours of a rotor-shaft system with internal damping composite materials under the action of a temperature field are analysed. The temperature field will increase the tangential force generated by the internal damping of the composite material. The tangential force will also increase with the rotor speed, which can destabilise the rotor-shaft system. To better understand the dynamic behaviours of the system, we introduced a finite element calculation model of a rotor-shaft system based on a 3D high-order element (Solid186) to study the turbocharger rotor-bearing system in a temperature field. The analysis was done according to the modal damping coefficient, stability limit speed, and unbalance response. The results show that accurate prediction of internal damping energy dissipation in a temperature field is crucial for accurate prediction of rotor dynamic performance. This is an important step to understand dynamic rotor stress and rotor dynamic design.

scholarly journals Parametric study on free vibration and instability of a functionally graded cracked shaft in a rotor-disc-bearing system: finite element approach

2018 ◽  
Vol 172 ◽  
pp. 03009 ◽  
Author(s):  
Debabrata Gayen ◽  
Debabrata Chakraborty ◽  
Rajiv Tiwari
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Functionally Graded ◽  
Outer Diameter ◽  
Open Crack ◽  
Fe Model ◽  
Internal Damping ◽  
Shaft System ◽  
Bearing System ◽  
Cracked Shaft

Free vibration and stability analysis are studied for a rotor-disk-bearing system having a radially functionally graded (FG) shaft with a transversely fully open crack, based on finite element (FE) approach. Both viscous and hysteretic internal damping are incorporated in the FE model of FG cracked shaft using two nodded Timoshenko beam element having four degrees of freedom (DOFs) at each node. Material properties of the FG cracked shaft are assumed temperature dependent and graded along radial direction following different material gradation law. FG shaft is made of two constituents material namely zirconia (ZrO2) and stainless steel (SS) where metallic (SS) contain is decreasing towards the outer diameter of the shaft. Extended Hamilton’s principle is employed to derive the system equations of motion (EOMs) of the FG cracked shaft system. A complete code is developed in MATLAB for correcting the formulation of modeling of crack and verified with existing published results. Influences of different material gradient index, temperature gradients, size and location of crack, viscous and hysteretic internal damping, slenderness ratio, and boundary condition on dynamic responses of the FG cracked shaft system are studied.

Optimal Parameters of an Electromagnetic Actuator for Actively Controlling the Vibration of a Flexible Rotor-Shaft System

2010 ◽  
Author(s):  
Anindya S. Das ◽  
Tarapada Roy ◽  
Jayanta K. Dutt
Keyword(s):  
Finite Element ◽  
Equations Of Motion ◽  
Electromagnetic Actuator ◽  
Flexible Rotor ◽  
Control Cost ◽  
Rotor Shaft ◽  
Shaft System ◽  
And Control ◽  
Optimal Set ◽  
Bearing System

The present work deals with finding the optimum parameter of a control system that utilizes an electromagnetic actuator to actively attenuate the vibration amplitude of a flexible rotor-shaft-bearing system. The equations of motion of the rotor-shaft-bearing system is found out using the finite element method and the rotor-shaft is modelled by beam finite element taking into account of the effects like distributed inertia, flexural stiffness, gyroscopic effect and internal material damping. Optimum actuator location and the optimal set of actuator and control parameters are found out using Genetic Algorithm based approach, where the objective is to minimize response amplitude with least amount of control cost with a specified margin of stability. The control parameter found in this approach is quite efficient in achieving the desired objective.

Vibration Analysis of Rotor-Bearing Systems With Internal Damping and Torsional Effects

1999 ◽  
Author(s):  
M. A. Mohiuddin ◽  
Y. A. Khulief ◽  
R. S. Al-Juruf
Keyword(s):  
Finite Element ◽  
Transverse Shear ◽  
Vibration Analysis ◽  
Dynamic Responses ◽  
Rotary Inertia ◽  
Internal Damping ◽  
Shear Deformations ◽  
Hysteretic Damping ◽  
Rotor Bearing ◽  
Bearing System

Abstract This paper extends the model of the linearly tapered Timoshenko shaft finite element developed by the authors to include the effect of internal viscous and hysteretic damping. The resulting model accounts, in addition to internal damping, for bending, rotary inertia, gyroscopic moments, transverse shear deformations and torsion. The developed model has been programmed in a fairly general way to be applicable to a general rotor-bearing system where both anisotropic bearings and internal damping are present. Numerical results of modal characteristics as well as dynamic responses are generated.

Natural frequency analysis of a functionally graded rotor-bearing system with a slant crack subjected to thermal gradients

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Arnab Bose ◽  
Prabhakar Sathujoda ◽  
Giacomo Canale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Law ◽  
Beam Theory ◽  
Functionally Graded ◽  
Thermal Gradients ◽  
Element Analysis ◽  
Rotor Bearing ◽  
Natural Frequency Analysis ◽  
Bearing System

Abstract The present work aims to analyze the natural and whirl frequencies of a slant-cracked functionally graded rotor-bearing system using finite element analysis for the flexural vibrations. The functionally graded shaft is modelled using two nodded beam elements formulated using the Timoshenko beam theory. The flexibility matrix of a slant-cracked functionally graded shaft element has been derived using fracture mechanics concepts, which is further used to develop the stiffness matrix of a cracked element. Material properties are temperature and position-dependent and graded in a radial direction following power-law gradation. A Python code has been developed to carry out the complete finite element analysis to determine the Eigenvalues and Eigenvectors of a slant-cracked rotor subjected to different thermal gradients. The analysis investigates and further reveals significant effect of the power-law index and thermal gradients on the local flexibility coefficients of slant-cracked element and whirl natural frequencies of the cracked functionally graded rotor system.

Improving Rotordynamic Performance of an Axial Flow Compressor With Two-Lobe Bearings Using Nonlinear Constraint Parameter Optimization

2011 ◽  
Author(s):  
Henning Ressing ◽  
Sebastian Kukla
Keyword(s):  
Parameter Optimization ◽  
Dynamic Performance ◽  
Axial Flow ◽  
Rotor Dynamics ◽  
Nonlinear Constraint ◽  
Design Variables ◽  
Rotor Bearing ◽  
Flow Compressor ◽  
Rotor Dynamic ◽  
Bearing System

Bearings are a key factor in achieving a good rotor dynamics performance for turbo machinery. Large compressors, steam and gas turbines for industrial applications are generally equipped with journal bearings either as tilting pad or multi-lobe bearing type. Here bearing parameters such as bearing geometry, bearing load or oil viscosity significantly alter bearing behavior and influence the rotor dynamics of the entire rotor-bearing system. In order to find an optimal set of bearing parameters for a given rotor-bearing system a nonlinear parameter optimization approach is employed. The rotor-bearing system is parameterized using bearing width, clearance and preload as design variables, since they represent design parameters that can be modified without significantly influencing the rotor design as a whole. The set of design variables is further constraint to stay within feasible limits of bearing design. The objective function is defined as a quantitative measure of rotor dynamic performance evaluating the distance from required separation margins with respect to rotor critical speeds based on API 617 7th Ed. In order to compute the objective function based on the design variables the bearing code ALP3T, solving Reynolds equations for the bearing fluid film, is used to compute the required stiffness and damping coefficients as input to the rotor dynamics program. The rotor dynamics performance is then evaluated using the rotor dynamics code SR3 based on the transfer matrix method. Both programs have been developed by the University of Braunschweig and are defacto industry standard within the German turbo machinery industry. The two programs are coupled and the nonlinear constraint optimization problem is solved using MATLAB’s optimization toolbox. The feasibility of this method is discussed based on an example of an axial flow compressor using two-lobe bearings. It is shown that a significant improvement in rotor dynamic performance can be achieved when compared to previous bearing selections for similar compressor designs and that the approach is suitable for a real-life engineering environment.

scholarly journals Stability Analysis of Symmetrical Rotor-Bearing Systems With Internal Damping Using Finite Element Method

1996 ◽  
Author(s):  
L. Forrai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Complex Form ◽  
Internal Damping ◽  
Bending Vibrations ◽  
Rotor Bearing ◽  
The Matrix ◽  
The Stability ◽  
Element Method

This paper deals with the stability analysis of self-excited bending vibrations of linear symmetrical rotor-bearing systems caused by internal damping using the finite element method. The rotor system consists of uniform circular Rayleigh shafts with internal viscous damping, symmetrical rigid disks, and discrete undamped isotropic bearings. By combining the sensitivity method and the matrix representation of the rotor dynamic equations in complex form to assess stability, it is proved theoretically that the stability threshold speed and the corresponding whirling speed coincide with the first forward critical speed regardless of the magnitude of the internal damping.

Study on Looseness and Impact - Rub Coupling Faults of a Vertical Dual-Disk Cantilever Rotor- Bearing System

2007 ◽  
Vol 353-358 ◽  
pp. 2479-2482
Author(s):  
Yan Jun Lu ◽  
Zhao Hui Ren ◽  
Hong Chen ◽  
Nai Hui Song ◽  
Bang Chun Wen
Keyword(s):  
Finite Element ◽  
Low Frequency ◽  
Element Model ◽  
Coupling Faults ◽  
Mechanics Model ◽  
Low Frequency Vibration ◽  
Rotor Bearing ◽  
Impact And Rubbing ◽  
The Impact ◽  
Bearing System

Because of wrong setting or long-term running of rotating machinery, the looseness may ouur in the bearing seats or bases. And also bring impact and rubbing of rotor-stator, That is the looseness and rub-impact coupling fault. In the paper,a mechanics model and a finite element model of a vertical dual-disk cantilever rotor- bearing system with coupling faults of looseness and rub-impact are set up. Based on the nonlinear finite element method and contact theory, the dynamical characteristices of the system under the influence of the looseness rigidity and impact-rub clearance is studied. The results show that the impact-rub of rotor-stator can reduce the low frequency vibration caused by looseness, and the impact-rub caused by looseness has obvious orientation. Also, the conclusion of diagnosing the looseness and rub-impact coupling faults is given in the end of the paper.

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

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nanshan Wang ◽  
Heng Liu ◽  
Yi Liu ◽  
Qidan Wang ◽  
Shemiao Qi ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Model ◽  
Dynamic Characteristics ◽  
3D Finite Element ◽  
Content Type ◽  
Rotor Bearing ◽  
Rod Fastening Rotor ◽  
3D Finite Element Method ◽  
Bearing System

Purpose This paper aims to examine the dynamic behaviours of a three-dimensional (3D) rod-fastening rotor bearing system (RFBS) with a crack in a fastening rod. Design/methodology/approach Based on the 3D finite element method model and stress analysis of a cracked RFBS, a 3D dynamic model of the RFBS with a crack in a fastening rod is established with considering the initial bending and stress redistribution caused by the crack. A combined numerical simulation technology is used to investigate the dynamic behaviours of the system. Findings The distribution of contact stress between the two disks will be not uniform, and the initial bending of the system will occur due to the presence of a crack. This will lead to the change of system stiffness and the dynamic behaviours such as vibration amplitude, and motion orbits will change significantly. Research limitations/implications A 3D finite element method dynamic model is proposed for the study of dynamic characteristics of complex combined rotor bearing system with cracks. Practical implications It is helpful and significant to master the dynamic behaviours of cracked RFBS. It is helpful to detect the presence of a crack of the rotor bearing system. Social implications Some of the losses caused by crack failure may be reduced. Originality/value The proposed 3D method can provide a useful reference for the study of dynamic characteristics of complex combined rotor bearing system with cracks. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0189

A Comparative Study Between Classical and Finite Element Model for Multilayer Viscoelastic Rotors

2015 ◽  
Author(s):  
H. Roy ◽  
S. Chandraker
Keyword(s):  
Finite Element ◽  
Dynamic Performance ◽  
Matrix Material ◽  
Stability Limit ◽  
Element Model ◽  
Constitutive Relationship ◽  
Rotor Shaft ◽  
Shaft System ◽  
Voigt Model ◽  
Relationship Of

Nowadays, heavy and bulky rotors are replaced by the light yet strong rotor, where the composite material is only supplementary. The composite may be constructed either by reinforcing long unidirectional fiber into matrix material or stacking of lamina, where each lamina has different orientation of fiber. But mathematical modelling of such type of rotor is little difficult when considering different orientation of fiber. This invokes us to construct multilayer rotors of different isotropic material and associated formulation to show its better dynamic performance. Generally internal damping has an enormous effect on the dynamics of rotor shaft system. For the sake of modelling, all layers are assumed to made of viscoelastic material and perfectly bonded. The constitutive relationship of each layer is represented by two element voigt model and equation of motion is obtained in time domain. This paper involves the development of both classical and finite element mathematical model of multilayer viscoelastic rotors, which contents system characteristics. Under these conditions, the complex modal behaviour of the rotor-shaft is studied to get an insight of the dynamic characteristics of the system, in terms of Decay rate, Stability Limit of Spin-speed, First Natural Frequency and also Unbalance frequency response.

Rotordynamics analysis of a quill-shaft coupling-rotor-bearing system

2014 ◽  
Vol 229 (8) ◽  
pp. 1385-1398 ◽  
Author(s):  
S Feng ◽  
HP Geng ◽  
L Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequency ◽  
Stiffness Matrix ◽  
Equation Of Motion ◽  
Numerical Results ◽  
The Finite Element Method ◽  
Rotor Bearing ◽  
Bearing System ◽  
Element Method

A quill-shaft coupling-rotor-bearing system is modeled and reported in this paper. The system consists of two rotors connected by a quill-shaft coupling in which each rotor is supported by two bearings. The stiffness matrix of the quill-shaft coupling is deduced and the equation of motion of the system is obtained by using the finite element method. Finally, the rotordynamics analysis of the system is conducted. The numerical results show that more frequency veering points occur for the quill-shaft coupling-rotor-bearing system compared with those of single rotor. In addition, the stiffness of the flexural element has significant effects on the first bending natural frequency of the quill shaft when the length of the quill shaft becomes shorter.

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