Effect of Varying the Number of Rollers on Dynamics of a Cylindrical Roller Bearing

2014 ◽  
Author(s):  
Aditya Sharma ◽  
M. Amarnath ◽  
P. K. Kankar
Keyword(s):  
Nonlinear Dynamic ◽  
Fourier Transforms ◽  
Roller Bearing ◽  
Hertzian Contact ◽  
Design Stage ◽  
Nonlinear Dynamic Model ◽  
Rotor Bearing ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller ◽  
Bearing System

In present paper, nonlinear dynamic model has been developed for cylindrical roller bearings. The Hertzian contact theory is used to derive a two degree of freedom model which considers nonlinearity due to clearance. The nonlinear dynamic behaviour of cylindrical roller bearing has been studied with varying number of rollers supporting load. The modified Newmark-β numerical integration technique has been used to solve the equations of motion. All the results are presented in the form of Fast Fourier Transforms and Poincarè maps. As the number of rollers is increases, system becomes stiffer. The results show that the number of rollers supporting load is one of the important parameters affecting the dynamics of rotor bearing system. Therefore, it must be considered at the design stage to understand the dynamic characteristics and stability of the rotor bearing system.

A New Quasi-Static Cylindrical Roller Bearing Model to Accurately Consider Non-Hertzian Contact Pressure in Time Domain Simulations

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Simon Kabus ◽  
Michael R. Hansen ◽  
Ole Ø. Mouritsen
Keyword(s):  
Fatigue Life ◽  
Time Domain ◽  
Roller Bearing ◽  
Rolling Bearing ◽  
Elastic Half Space ◽  
Hertzian Contact ◽  
Fatigue Life Analysis ◽  
Cylindrical Roller Bearing ◽  
Six Degree Of Freedom ◽  
Cylindrical Roller

The accuracy of the fatigue life calculations in rolling bearing simulations is highly dependent on the precision of the roller-raceway contact simulations. Several different methods exist to simulate these pressure distributions and in time domain bearing simulations, where many contacts need evaluation, the simple and time efficient methods are more popular, yielding erroneous life estimates. This paper presents a new six degree of freedom frictionless quasi-static time domain cylindrical roller bearing model that uses high precision elastic half-space theory to simulate the contact pressures. The potentially higher computational demand using the advanced contact calculations is addressed by preprocessing a series of contacts at different centerline approaches and roller tilt angles, which are used for interpolating contact results during time domain simulations. It is demonstrated that this new model allows for simulation of bearing misalignments, roller centrifugal forces, and flange contact induced roller tilt moments, and that the effect of these conditions is directly evaluated in a detailed fatigue life analysis. Finally, the stiffness of the bearing model is validated against existing experimental data with good correlation.

Study on Bifurcation of Rigid Rotor Roller Bearings System Considering Nonlinear Dynamic Behavior

2010 ◽  
Vol 34-35 ◽  
pp. 467-471
Author(s):  
Li Cui ◽  
Jian Rong Zheng
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Roller Bearing ◽  
Radial Clearance ◽  
Rigid Rotor ◽  
Rotating Speed ◽  
Rotor Bearing ◽  
Nonlinear Dynamic Behavior ◽  
Bifurcation And Stability ◽  
Bearing System

Rigid rotor roller bearing system displays complicated nonlinear dynamic behavior due to nonlinear Hertzian force of bearing. Nonlinear bearing forces of roller bearing and dynamic equations of rotor bearing system are established. The bifurcation and stability of the periodic motion of the system in radial clearance-rotating speed and ellipticity-rotating speed parametric domains are studied by use of continuation-shooting algorithm for periodic solutions of nonlinear non-autonomous dynamics system. Results show that the parameters of rotor bearing system should be designed carefully in order to obtain period-1 motion.

scholarly journals Nonlinear Dynamic Analysis of Rotor-Bearing System with Cubic Nonlinearity

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Guofang Nan ◽  
Yujie Zhu ◽  
Yang Zhang ◽  
Wei Guo
Keyword(s):  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Hertzian Contact ◽  
Stable Operation ◽  
Nonlinear Stiffness ◽  
Cubic Nonlinearity ◽  
Dynamic Behaviors ◽  
Mass Eccentricity ◽  
Rotor Bearing ◽  
Bearing System

Nonlinear dynamic characteristics of a rotor-bearing system with cubic nonlinearity are investigated. The comprehensive effects of the unbalanced excitation, the internal clearance, the nonlinear Hertzian contact force, the varying compliance vibration, and the nonlinear stiffness of support material are considered. The expression with the linear and the cubic nonlinear terms is adopted to characterize the synthetical nonlinearity of the rotor-bearing system. The effects of nonlinear stiffness, rotating speed, and mass eccentricity on the dynamic behaviors of the system are studied using the rotor trajectory diagrams, bifurcation diagrams, and Poincaré map. The complicated dynamic behaviors and types of routes to chaos are found, including the periodic doubling bifurcation, sudden transition, and quasiperiodic from periodic motion to chaos. The research results show that the system has complex nonlinear dynamic behaviors such as multiple period, paroxysmal bifurcation, inverse bifurcation, jumping phenomena, and chaos; the nonlinear characteristics of the system are significantly enhanced with the increase of the nonlinear stiffness, and the material with lower nonlinear stiffness is more conducive to the stable operation of the system. The research will contribute to a comprehensive understanding of the nonlinear dynamics of the rotor-bearing system.

Establishment of Nonlinear Dynamic Model for Prediction of Rotordynamic Instability of Steam Turbine Rotor-Bearing System Caused by Partial Admission

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Ying Cui ◽  
Zhansheng Liu ◽  
Daren Yu ◽  
Yanfeng Duan
Keyword(s):  
Steam Turbine ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Turbine Rotor ◽  
Nonlinear Dynamic Model ◽  
Steam Turbine Rotor ◽  
Rotor Bearing ◽  
Partial Admission ◽  
Bearing System

A nonlinear dynamic model is developed for a rotor-bearing system with radial steam force due to partial admission, taking into account the prediction of subsynchronous instability of a steam turbine. The optimum schemes are obtained by comparing the rotor responses subjected to maximal radial steam forces in different partial admission schemes. It is found through comparison that the instability of a rotor-bearing system is directly related to the direction of the radial steam force in the partial admission scheme.

Vibration Analysis of a Roller Bearing With a Bump Defect

2018 ◽  
Author(s):  
Zhifeng Shi ◽  
Jing Liu ◽  
Zaigang Chen ◽  
Yimin Shao
Keyword(s):  
Roller Bearing ◽  
Vibration Characteristics ◽  
Time Varying ◽  
Nonlinear Dynamic Model ◽  
Roller Bearings ◽  
Defect Profile ◽  
Localized Defects ◽  
Simulation Results ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Vibration performances of roller bearings are greatly affected by various localized defects. Thus, it is very important to analyze vibration characteristics of the roller bearings with the localized defects. In this paper, a nonlinear dynamic model is developed to formulate the effect of a localized defect on the vibration characteristics of a cylindrical roller bearing (CRB). A bump defect is formulated in this model. The defect profile is defined as a spherical one. The time-varying displacement excitation caused by the defect is modelled. Effects of the defect sizes on the vibration characteristics of the roller bearing are discussed. The simulation results show that the developed method can provide some guidance for understanding the vibration characteristics of the CRB with a bump defect.

Influence of Lubricant Traction Coefficient on Cage's Nonlinear Dynamic Behavior in High-Speed Cylindrical Roller Bearing

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Wenhu Zhang ◽  
Sier Deng ◽  
Guoding Chen ◽  
Yongcun Cui
Keyword(s):  
Dynamic Response ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Roller Bearing ◽  
Mass Center ◽  
Nonlinear Dynamic Response ◽  
Traction Coefficient ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

In this paper, the formulas of elastohydrodynamic traction coefficients of four Chinese aviation lubricating oils, namely, 4109, 4106, 4050, and 4010, were obtained by a great number of elastohydrodynamic traction tests. The nonlinear dynamics differential equations of high-speed cylindrical roller bearing were built on the basis of dynamic theory of rolling bearings and solved by Hilber–Hughes–Taylor (HHT) integer algorithm with variable step. The influence of lubricant traction coefficient on cage's nonlinear dynamic behavior was investigated, and Poincaré map was used to analyze the influence of four types of aviation lubricating oils on the nonlinear dynamic response of cage's mass center. The period of nonlinear dynamic response of cage's mass center was used to assess cage's stability. The results of this paper provide the theoretical basis for selection of aviation lubricating oil.

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