scholarly journals Vibration Response Analysis of a Gear-rotor-bearing System Considering Steady-state Temperature

2021 ◽  
Author(s):  
Zhou Sun ◽  
Siyu Chen ◽  
Zehua Hu ◽  
Duncai Lei
Keyword(s):  
Steady State ◽  
Material Properties ◽  
Temperature Fields ◽  
Response Analysis ◽  
Nodal Method ◽  
Steady State Temperature ◽  
Rotor Bearing ◽  
Influence Of Temperature On ◽  
Bearing Force ◽  
Bearing System

Abstract As an important factor leading to the failure of gear system, the study of thermal effect is insufficiently deep. Based on the finite element nodal method, a more comprehensive dynamic model of gear-rotor-bearing system is established, which considers the thermal related material properties, time-varying meshing stiffness (TVMS), backlash and friction, gyroscopic effect. The constitutive relation of beam element considering steady-state temperature is reconstructed, and thermal node load is formulated. Considering the influence of temperature on the material properties of flexible shaft and gear, the thermal related TVMS and thermal backlash are obtained. The dynamic response of the system under different steady-state temperature fields is compared, and the influence of hot backlash is studied, then the thermal related vibration characteristics are obtained. Besides, the influence of bearing type on bearing force and axial trajectory is studied. The results show that the system motion changes from period to chaos with the temperature increase in part of the speed range. The appropriate backlash is helpful to restrain the chaotic motion caused by temperature rise. Moreover, the temperature can significantly increase the axial bearing force, and the appropriate bearing can reduce the axial displacement.

Nonlinear Dynamics of Flexible Rotors Supported on Journal Bearings—Part I: Analytical Bearing Model

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Mohammad Miraskari ◽  
Farzad Hemmati ◽  
Mohamed S. Gadala
Keyword(s):  
Journal Bearing ◽  
Nonlinear Coefficient ◽  
Journal Bearings ◽  
Flexible Rotor ◽  
Dynamic Coefficients ◽  
Flexible Rotors ◽  
Rotor Bearing ◽  
Bearing Force ◽  
Derivatives Of ◽  
Bearing System

To determine the bifurcation types in a rotor-bearing system, it is required to find higher order derivatives of the bearing forces with respect to journal velocity and position. As closed-form expressions for journal bearing force are not generally available, Hopf bifurcation studies of rotor-bearing systems have been limited to simple geometries and cavitation models. To solve this problem, an alternative nonlinear coefficient-based method for representing the bearing force is presented in this study. A flexible rotor-bearing system is presented for which bearing force is modeled with linear and nonlinear dynamic coefficients. The proposed nonlinear coefficient-based model was found to be successful in predicting the bifurcation types of the system as well as predicting the system dynamics and trajectories at spin speeds below and above the threshold speed of instability.

Analysis of an Accelerating Rotor-Bearing System With Flexible Damped Supports

1998 ◽  
Author(s):  
Euro L. Casanova ◽  
Luis U. Medina
Keyword(s):  
Steady State ◽  
Numerical Integration ◽  
Equations Of Motion ◽  
Peak Amplitude ◽  
Graphical Form ◽  
Jeffcott Rotor ◽  
Rotor Bearing ◽  
Flexible Supports ◽  
Steady State Predictions ◽  
Bearing System

This paper deals with the dynamics of an accelerating unbalanced Jeffcott rotor-bearing system mounted on damped, flexible supports. The general equations of motion for such a system are presented and discussed. The rotor response was predicted, via numerical integration, for various cases in runup and rundown conditions and presented in graphical form. The effects of acceleration on the rotor peak amplitude and the speed at which the peak occurs is discussed and compared to steady state predictions.

Stability and response analysis of symmetrical single-disk flexible rotor-bearing system

2005 ◽  
Vol 38 (8) ◽  
pp. 749-756 ◽  
Author(s):  
Sanxing Zhao ◽  
Hua Xu ◽  
Guang Meng ◽  
Jun Zhu
Keyword(s):  
Response Analysis ◽  
Flexible Rotor ◽  
Rotor Bearing ◽  
Single Disk ◽  
Bearing System

Response Analysis of a General Asymmetric Rotor-Bearing System

1980 ◽  
Vol 102 (1) ◽  
pp. 147-157 ◽  
Author(s):  
T. Inagaki ◽  
H. Kanki ◽  
K. Shiraki
Keyword(s):  
Dynamic Properties ◽  
Equations Of Motion ◽  
Harmonic Balance Method ◽  
Field Measurements ◽  
Transverse Mass ◽  
Response Analysis ◽  
Mass Moment ◽  
Rotor Bearing ◽  
Asymmetric Rotor ◽  
Bearing System

This paper presents an analytical method for the evaluation of the synchronous response of a general asymmetric rotor-bearing system. In the analysis, slightly asymmetric shaft stiffness in bending and shearing, which distribute along the rotor, and asymmetric transverse mass moment of inertia are considered. The dynamic properties of bearings and pedestals are assumed to be anisotropic and coupled in each direction. The equations of motion with periodic time dependent coefficients are solved by the Harmonic Balance Method and formulated to the transfer matrix. These solutions include the “Modified Holzer-Myklestad-Prohl Method by Lund & Orcutt” as a special case. The results of the analysis are confirmed by a simple model test and field measurements of large turbosets.

Dynamic Response of a Geared Rotor-Bearing System Under Residual Shaft Bow Effect

2006 ◽  
Author(s):  
T. N. Shiau ◽  
E. K. Lee ◽  
Y. C. Chen ◽  
T. H. Young
Keyword(s):  
Steady State ◽  
Natural Frequencies ◽  
Coupling Effect ◽  
Equations Of Motion ◽  
Transmission Error ◽  
Mode Shapes ◽  
Steady State Response ◽  
State Response ◽  
Rotor Bearing ◽  
Bearing System

The paper presents the dynamic behaviors of a geared rotor-bearing system under the effects of the residual shaft bow, the gear eccentricity and excitation of gear’s transmission error. The coupling effect of lateral and torsional motions is considered in the dynamic analysis of the geared rotor-bearing system. The finite element method is used to model the system and Lagrangian approach is applied to derive the system equations of motion. The dynamic characteristics including system natural frequencies, mode shapes and steady-state response are investigated. The results show that the magnitude of the residual shaft bow, the phase angle between gear eccentricity and residual shaft bow will significantly affect system natural frequencies and steady-state response. When the spin speed closes to the second critical speed, the system steady state response will be dramatically increased by the residual shaft bow for the in-phase case. Moreover the zero response can be obtained when the system is set on special conditions.

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