Systematical Analysis Method for the Mechanical Behaviors of Crankshaft-Bearing System

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Changlin Gui ◽  
Jun Sun ◽  
Zhixian He ◽  
Zhen Li
Keyword(s):  
Elastic Deformation ◽  
Dynamic Stress ◽  
Analysis Method ◽  
Mechanical Behaviors ◽  
Remarkable Effect ◽  
Journal Misalignment ◽  
Bearing System

Various mechanical behaviors will happen at the same time when an engine operates. Based on this concept, in this paper, a systematical analysis method is presented to analyze the multiple mechanical behaviors (tribology, dynamics, stiffness, and strength) of the crankshaft-bearing system in an engine. By this method, the analyses of the tribology of bearing, the dynamics of crankshaft-bearing system and the dynamic stress of crankshaft can be accomplished simultaneously. For example, the effect of the journal misalignment of crankshaft and the elastic deformation of bearing bush on the dynamics of crankshaft-bearing system, the tribological performances of main bearings and the dynamic stress of crankshaft are analyzed emphatically. The results show that the journal misalignment of crankshaft and the elastic deformation of bearing bush have remarkable effect on the tribological performances of main bearings and the dynamic stress of crankshaft, but have little effect on the dynamics of crankshaft-bearing system.

A Dynamic Simulation Approach to Machine Component Life Prediction

1988 ◽  
Author(s):  
T. S. Liu ◽  
E. J. Haug ◽  
B. Dopker
Keyword(s):  
Fatigue Life ◽  
Stress Analysis ◽  
Elastic Deformation ◽  
Life Prediction ◽  
Dynamic Stress ◽  
Subsequent Paper ◽  
Simulation Approach ◽  
Analysis Method ◽  
Deformation Method ◽  
Dynamic Stress Analysis

Abstract A system simulation approach is presented for dynamic stress analysis and life prediction of components of machines that undergo nonsteady gross motion and elastic deformation. The method employs finite element structural analysis, coupled gross motion-elastic deformation dynamics, and computer-based fatigue analysis, A computer aided engineering methodology is developed for life prediction by linking together software from dynamics, structures, and fatigue life estimation; to compliment conventional fatigue experiments. Dynamic stress analysis is carried out using either an uncoupled gross motion-elastic deformation method or a more accurate approach that takes into account the coupling between large displacements and elastic deformation. With the aid of vehicle operational scenarios, stress/strain histories at critical regions in vehicle components during a projected service life are simulated. A local strain approach is used to calculate cumulative fatigue damage at notches, which is used in assessing fatigue life of components during the design phase; i.e., prior to availability of experimental data A vehicle example is presented, using a simplified dynamic-stress analysis method. The more general and accurate fully coupled dynamic-stress analysis method will be illustrated in a subsequent paper.

Hybrid Fatigue Analysis Method for Railway Carbody Structure

2008 ◽  
Vol 44-46 ◽  
pp. 733-738 ◽  
Author(s):  
Bing Rong Miao ◽  
Wei Hua Zhang ◽  
Shou Ne Xiao ◽  
Ding Chang Jin ◽  
Yong Xiang Zhao
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Hybrid Method ◽  
Dynamic Stress ◽  
Stress Test ◽  
Fatigue Analysis ◽  
Railway Vehicle ◽  
Analysis Method ◽  
Structure Dynamic ◽  
Multi Body

Railway vehicle structure fatigue life consumption monitoring can be used to determine fatigue damage by directly or indirectly monitoring the loads placed on critical vehicle components susceptible to failure from fatigue damage. The sample locomotive carbody structure was used for this study. Firstly, the hybrid fatigue analysis method was used with Multi-Body System (MBS) simulation and Finite Element Method (FEM) for evaluating the carbody structure dynamic stress histories. Secondly, the standard fatigue time domain method was used in fatigue analysis software FE-FATIGUE and MATLAB WAFO (Wave Analysis for Fatigue and Oceanography) tools. And carbody structure fatigue life and fatigue damage were predicted. Finally, and carbody structure dynamic stress experimental data was taken from this locomotive running between Kunming-Weishe for this analysis. The data was used to validate the simulation results based on hybrid method. The analysis results show that the hybrid method prediction error is approximately 30.7%. It also illustrates that the fatigue life and durability of the locomotive can be predicted with this hybrid method. The results of this study can be modified to be representative of the railway vehicle dynamic stress test.

Dynamic Characteristics of TEHD Tilt Pad Journal Bearing Simulation Including Multiple Mode Pad Flexibility Model

1993 ◽  
Author(s):  
Jinsang Kim ◽  
Alan Palazzolo
Keyword(s):  
Heat Transfer ◽  
Elastic Deformation ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Variable Viscosity ◽  
Global Analysis ◽  
Analysis Method ◽  
Stiffness And Damping ◽  
Modal Coordinates ◽  
Good Agreement

Abstract An approach for incorporating the heat transfer and elastic deformation effects into dynamic coefficient calculation is presented. A global analysis method is used, which finds the equilibrium pad tilt angles at each eccentricity position and includes cross-film variable viscosity, heat transfer effects in the lubricant, elastic deformation, heat conduction effects in the pads, and elastic deformation effect in the pivots. Deflection modes are used to approximate deformation of the top surface of the pads. The dynamic coefficients of a single pad are calculated at the equilibrium state of the bearing, based on numerical perturbation with respect to the bearing degrees of freedom. These include journal position, pad rotation, pivot deformation, and modal coordinates. The stiffness and damping coefficients are calculated and show very good agreement with experimental and numerical results from the existing literature.

Numerical analysis of the transient wear and lubrication behaviors of misaligned journal bearings caused by linear shaft misalignment

2021 ◽  
pp. 1-17
Author(s):  
Tianyou Yang ◽  
Yanfeng Han ◽  
Yijia Wang ◽  
Guo Xiang
Keyword(s):  
Numerical Model ◽  
Film Thickness ◽  
Contact Pressure ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Fluid Pressure ◽  
Axial Direction ◽  
Wear Depth ◽  
Wear Process ◽  
Journal Misalignment

Abstract The purpose of this study is to investigate the role of the misalignment journal, caused by journal elastic deformation, on the transient wear and mixed lubrication performances using a numerical model. In the numerical model, the transient geometry lubrication clearance considering the journal misalignment, the transient elastic deformation and the transient wear depth are incorporated to evaluate the transient film thickness during wear process. The evolutions, under different external loads, of the wear depth, wear rate, elastic deformation, film thickness, fluid pressure and contact pressure are calculated by the numerical model. Furthermore, the calculated results of the misaligned journal bearing are compared with those of the aligned journal bearing. The results show that the distributions of the wear depth, film pressure and elastic deformation are asymmetric along the axial direction and the peak values of them shift toward the back end when the journal misalignment is considered. The maximum wear depth, maximum fluid pressure, maximum contact pressure and maximum elastic deformation of the misaligned journal condition are significantly larger than those of the aligned journal condition.

An analysis method to determine how changes in dynamic complexity impact on rotor-bearing systems

2020 ◽  
pp. 095440622095488
Author(s):  
Mian Jiang ◽  
Shuangqi Liu ◽  
Yuhua Wang
Keyword(s):  
Condition Monitoring ◽  
Lubricating Oil ◽  
Analysis Method ◽  
Dynamic Complexity ◽  
Rotor Systems ◽  
Methodological Choices ◽  
Rotor Bearing ◽  
Nonlinearity Measures ◽  
Monitoring Performance ◽  
Bearing System

Condition monitoring performance and diagnosis of rotor-bearing systems depend not only on the methods used, but also on the dynamic complexity of the system itself. Thus, it is important to analyze how changes in parameters under various working conditions impact on dynamic complexity. Most of previous research efforts on this topic have been focused on the analysis of nonlinear dynamics of rotor-bearing systems with different parameters. In this paper, a nonlinearity quantification based analysis method is presented to determine how parameter dynamics impact the complexity of rotor-bearing systems. The dynamic complexity of rotor system is estimated using defined nonlinearity measures. To validate this method, a sliding rotor-bearing system with a loose pedestal is used. The estimates (nonlinearity degrees) and the states of motion are matched with increasing rotational speeds. It is then investigated, how the eccentricities, lubricating oil viscosities, and bearing clearances impacted the dynamic complexity at several critical rotational speeds. These results can guide methodological choices for condition monitoring and diagnosis of rotor systems.

A Study of Misaligned Micropolar Lubricated Membrane Compensated Hybrid Journal Bearing System

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Satish C. Sharma ◽  
E. Rajasekhar Nicodemus ◽  
Nathi Ram
Keyword(s):  
Reynolds Equation ◽  
Flow Characteristic ◽  
Journal Bearing ◽  
Lubricating Oil ◽  
Micropolar Theory ◽  
Shaft Deflection ◽  
Journal Misalignment ◽  
Raphson Method ◽  
System Operating ◽  
Bearing System

The present work aims to analytically study the performance of misaligned four-pocket, membrane compensated, hybrid journal bearing system operating with micropolar lubricant. In the present study, the flow characteristic of the lubricating oil containing additives and contaminants has been modeled using Erigen’s micropolar theory. The journal misalignment which may occur as a result of noncentral loading, improper assembly, shaft deflection due to elasticity and thermal distortions, etc. has been accounted for in the present study by defining a pair of misalignment parameters in vertical and horizontal directions (i.e., δ and σ).The modified Reynolds equation governing the flow of micropolar lubricant in the clearance space of a misaligned bearing has been solved using FEM and Newton Raphson method along with the appropriate boundary conditions. The numerically simulated results suggest that the effect of journal misalignment is to cause degradation in bearing performance, whereas the influence of micropolar effect of lubricant is to enhance the bearing performance. Therefore, it is imperative to account for the effect of misalignment and lubricant behavior during the design process in order to generate accurate bearing characteristics data.

Comparison of Effects of Dimensional Manufacturing Tolerances and Journal Out-of-Roundness on Stability of Hydrodynamic Journal Bearing System

2011 ◽  
Vol 121-126 ◽  
pp. 1966-1971
Author(s):  
Wu Bin Xu ◽  
De Jian Zhou ◽  
Peter Ogrodnik ◽  
Mike Goodwin
Keyword(s):  
Theoretical Analysis ◽  
Taguchi Method ◽  
Journal Bearing ◽  
Journal Bearings ◽  
System Stability ◽  
Design Stage ◽  
Analysis Method ◽  
Manufacturing Tolerances ◽  
Hydrodynamic Journal Bearing ◽  
Bearing System

The manufacturing tolerances of a hydrodynamic journal bearing system are inevitable in manufacturing process. To examine and understand the effect of manufacturing tolerances on the system stability can help engineers to confidently choose reasonable tolerances at design stage. This study presented a theoretical analysis method to determine and compare the effects of dimensional manufacturing tolerances and journal out-of-roundness on system stability by Taguchi method. The results show that the journal out-of-roundness has the most significant effect on the system stability and the journal out-of-roundness appears to stabilize the system. The authors suggest that both dimensional manufacturing tolerances and journal roundness should be taken into account in the design of cylindrical journal bearings.

Auxiliary Bearing System Optimization for AMB Supported Rotors Based on Rotor Drop Analysis: Part I — Rotor Drop Analysis Method

2016 ◽  
Author(s):  
Jianming Cao ◽  
Paul Allaire ◽  
Timothy Dimond ◽  
Saeid Dousti
Keyword(s):  
Ball Bearing ◽  
System Optimization ◽  
American Petroleum Institute ◽  
Operating Conditions ◽  
Rolling Element Bearing ◽  
Hertzian Contact ◽  
Analysis Method ◽  
Contact Loads ◽  
Auxiliary Bearing ◽  
Bearing System

For rotors supported with active magnetic bearings (AMBs), the auxiliary bearing system or backup bearing system is needed to avoid serious potential internal damaging in the event of AMB loss of power or overload. The evolution of auxiliary systems has been made a priority by the American Petroleum Institute using analytical or experimental methods. In part I of this paper, a detailed rotor drop nonlinear transient analysis method including flexible shaft, rolling element bearing components including inner/outer races and balls, as well as flexible/damped supporting structures is given. A finite element based 6-DOF flexible rotor model is used to indicate shaft motion before the drop (operating conditions) and during the rotor drop event. Un-lubricated Hertzian contact models are used between the shaft and inner/outer races, between balls and races. To avoid heavy calculating time, two different methods to calculate ball bearing contact loads are discussed and the simulation results are compared. These models are applied to predict shaft-race-ball displacements and angular speeds, contact loads and ball bearing stresses during the drop for angular contact auxiliary bearings. This method also can be used to design and optimize the auxiliary bearing system as presented in the 2nd part of this paper.

Reliability Sensitivity Analyses for Oil Whip in Rotor-Bearing System

2012 ◽  
Vol 538-541 ◽  
pp. 1967-1970
Author(s):  
Chang Qing Su ◽  
Yi Yu Sun ◽  
Le Xin Li
Keyword(s):  
High Speed ◽  
Sensitivity Analyses ◽  
Analysis Method ◽  
Random Parameters ◽  
Work Condition ◽  
Oil Whip ◽  
Reliability Sensitivity ◽  
Rotor Bearing ◽  
The Common ◽  
Bearing System

Oil whip phenomenon is the common fault in rotor-bearing system. The reason why oil whip happens often has been researched in high-speed rotor-bearing system. But in practice engineering, due to the requirement of work condition, oil whip cannot be avoided all the time in rotor-bearing system. The paper is based on the relation criterion of oil whip happens in rotor-bearing system, the reliability mode and system reliability of oil whip are defined, and the reliability analysis method for avoiding oil whip in rotor-bearing system is carried out. The effect on reliability sensitivity of random parameters is studied. Numerical results are also presented and discussed.

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