scholarly journals Fatigue Life Analysis of Rolling Bearings Based on Quasistatic Modeling

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Guo ◽  
Hongrui Cao ◽  
Zhengjia He ◽  
Laihao Yang
Keyword(s):  
Fatigue Life ◽  
Great Influence ◽  
Prediction Method ◽  
Coupling Model ◽  
Accelerated Life Test ◽  
Rolling Bearings ◽  
Accelerated Life ◽  
Bearing Life ◽  
Rolling Elements ◽  
Fatigue Life Analysis

Rolling bearings are widely used in aeroengine, machine tool spindles, locomotive wheelset, and so forth. Rolling bearings are usually the weakest components that influence the remaining life of the whole machine. In this paper, a fatigue life prediction method is proposed based on quasistatic modeling of rolling bearings. With consideration of radial centrifugal expansion and thermal deformations on the geometric displacement in the bearings, the Jones’ bearing model is updated, which can predict the contact angle, deformation, and load between rolling elements and bearing raceways more accurately. Based on Hertz contact theory and contact mechanics, the contact stress field between rolling elements and raceways is calculated. A coupling model of fatigue life and damage for rolling bearings is given and verified through accelerated life test. Afterwards, the variation of bearing life is investigated under different working conditions, that is, axial load, radial load, and rotational speed. The results suggested that the working condition had a great influence on fatigue life of bearing parts and the order in which the damage appears on bearing parts.

scholarly journals Fatigue Life Prediction of Rolling Bearings Based on Modified SWT Mean Stress Correction

2020 ◽  
Author(s):  
Aodi Yu ◽  
Hong-Zhong Huang ◽  
Yan-Feng Li ◽  
He Li ◽  
Ying Zeng
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Stress Ratio ◽  
Prediction Models ◽  
Great Influence ◽  
Sensitivity Coefficient ◽  
Model Verification ◽  
Mean Stress ◽  
Test Results ◽  
Rolling Bearings

Abstract Mean stress has a great influence on fatigue life, commonly used stress-based life prediction models can only fit the test results of fatigue life under specific stress ratio or mean stress but cannot describe the effect of stress ratio or mean stress on fatigue life. Smith, Watson and Topper (SWT) proposed a simple mean stress correction criterion. However, the SWT model regards the sensitivity coefficient of all materials to mean stress as 0.5, which will lead to inaccurate predictions for materials with a sensitivity coefficient not equal to 0.5. In this paper, considering the sensitivity of different materials to mean stresses, compensation factor is introduced to modify the SWT model, and several sets of experimental data are used for model verification. Then, the proposed model is applied to fatigue life predictions of rolling bearings, and the results of proposed method are compared with test results to verify its accuracy.

Reliability Prediction for a Thermal System Using CFD and FEM Simulations

2008 ◽  
Author(s):  
O. M. Al-Habahbeh ◽  
D. K. Aidun ◽  
P. Marzocca ◽  
H. Lee
Keyword(s):  
Thermal Analysis ◽  
Fatigue Life ◽  
Cfd Simulation ◽  
General Procedure ◽  
Prediction Method ◽  
Reliability Prediction ◽  
Parameters Uncertainty ◽  
Computational Fluid Dynamics Cfd ◽  
Fatigue Life Analysis ◽  
Cylindrical Ring

A general procedure for reliability prediction is introduced. The procedure is applied to a cylindrical ring and can be used for any similar thermal application. The procedure is classified as a physics-based reliability prediction method. It utilizes different computational tools such as Computational Fluid Dynamics (CFD), Finite Element Method (FEM), and Monte Carlo Simulations (MCS). The process starts with CFD simulation to find the convective terms necessary for the transient FEM thermal analysis. The transient FEM thermal analysis provides values for thermal stress. These values are used in the fatigue life analysis. The end result is the fatigue life of the component. As a result of input parameters uncertainty, the resulting life will be in the form of a Probability Density Function (PDF), which enables the calculation of the reliability of the component.

scholarly journals Dynamic Influence of Wheel Flat on Fatigue Life of the Traction Motor Bearing in Vibration Environment of a Locomotive

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5810
Author(s):  
Bingbin Guo ◽  
Zhixiang Luo ◽  
Bo Zhang ◽  
Yuqing Liu ◽  
Zaigang Chen
Keyword(s):  
Fatigue Life ◽  
Prediction Models ◽  
Prediction Method ◽  
Rolling Bearing ◽  
Traction Motor ◽  
Gear Mesh ◽  
Impact Forces ◽  
Bearing Life ◽  
Bearing Loads ◽  
Wheel Flat

Wheel flat can cause a large impact between the wheel and rail and excites a forced vibration in the locomotive and track structure systems. The working conditions and fatigue life of the motor bearings are significantly affected by the intensified wheel–rail interaction via the transmission path of the gear mesh. In this study, a fatigue life prediction method of the traction motor bearings in a locomotive is proposed. Based on the L−P theory or ISO 281 combined with the Miner linear damage theory and vehicle–track coupled dynamics, the irregular loads induced by the track random irregularity and gear mesh are considered in this proposed method. It can greatly increase the accuracy of predictions compared with the traditional prediction models of a rolling bearing life whose bearing loads are assumed to be constant. The results indicate that the periodic impact forces and larger mesh forces caused by the wheel flat will reduce the fatigue life of the motor bearings, especially when the flat length is larger than 30 mm. Using this method, the effects of the flat length and relatively constant velocity of the locomotive are analyzed. The proposed method can provide a theoretical basis to guarantee safe and reliable working for motor bearings.

Accelerated Fatigue Life Testing of Nicr-Cr3C2 Coating at Different Loads under Rolling Contact Condition

2012 ◽  
Vol 472-475 ◽  
pp. 13-18
Author(s):  
Shao Yun Wang ◽  
Guo Lu Li ◽  
Hai Dou Wang ◽  
Jin Hai Liu ◽  
Bin Shi Xu
Keyword(s):  
Fatigue Life ◽  
Steel Substrate ◽  
Contact Condition ◽  
Rolling Contact ◽  
Accelerated Life Test ◽  
Al Alloy ◽  
Accelerated Life ◽  
Life Model ◽  
Life Tests ◽  
Failure Life

The aim of this paper is to address the accelerated fatigue life under rolling contact condition of coatings. The NiCr-Cr3C2ceramic-metal and Ni-Al alloy were deposited on steel substrate as topcoating and undercoating using supersonic plasma spraying technique, respectively. Accelerated fatigue life tests were conducted using a ball-on-disc tester. The life of coatings was evaluated by Weibull distribution plots and the accelerated fatigue life model was established. The results showed that the coupling relationship between the load and failure life of coatings could be obtained using this model. Accelerated life test for fatigue of coatings could improve the experimental efficiency.

Fatigue Life Analysis of Storage Tanks In-Service Based on Exponential Curve Settlement Prediction Model

2018 ◽  
Author(s):  
Delin Zhang ◽  
Zhiping Chen ◽  
You Li
Keyword(s):  
Fatigue Life ◽  
Prediction Model ◽  
Prediction Method ◽  
Element Model ◽  
Contact Condition ◽  
Storage Tanks ◽  
Settlement Prediction ◽  
Structural Fatigue ◽  
Exponential Curve ◽  
Fatigue Life Analysis

In order to study the structural fatigue safety of in-service fixed roof storage tanks after uneven settlement, an exponential curve method of settlement prediction has been constructed. A finite element model based on the contact condition between the elastic ring beam foundation and the tank base was also proposed. On the basis of above, a fatigue life prediction method of in-service storage tanks based on the settlement prediction model has been established. Combined with the engineering example of an in-service tank, the structural fatigue safety under the actual uneven settlement was analyzed. The results indicate that the trend of foundation settlement with time could be predicted accurately and the contact condition between base and foundation could be simulated simultaneously. Subsequently, the in-service tank’s structural fatigue life under the uneven settlement could be predicted.

On the Accuracy of Rolling Bearing Fatigue Life Prediction

1996 ◽  
Vol 118 (2) ◽  
pp. 297-309 ◽  
Author(s):  
T. A. Harris ◽  
J. I. McCool
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Prediction Method ◽  
Rolling Bearing ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Critical Design ◽  
Bearing Life ◽  
Limit Stress ◽  
Fatigue Endurance

Ball and roller bearings are designed to meet endurance requirements basically determined according to the Standard fatigue life calculation method. This method is based on the Lundberg-Palmgren fatigue life theory as modified by reliability, material, and lubrication factors. As application load and spied requirements have increased, the Lundberg-Palmgren method has resulted in bearings of increased size, adding unnecessarily to the size and weight of mechanisms. This is a critical design situation for weight and size-sensitive components such as aircraft gas turbine engines and helicopter power transmissions. The bearing life prediction method developed by Ioannides and Harris recognizes the existence of a fatigue limit stress. If the stresses an operating bearing experiences do not exceed the limit stress, the bearing can achieve infinite life. In any case, the method tends to predict longer lives than the Lundberg-Palmgren method. This paper evaluates the life prediction accuracies of the Lundberg-Palmgren and Ioannides-Harris methods by comparing lives calculated according to these methods and to those actually experienced in 62 different applications. As a result of the investigation, the Ioannides-Harris method is shown to more accurately predict bearing fatigue endurance.

Bearing life prognosis under environmental effects based on accelerated life testing

2002 ◽  
Vol 216 (5) ◽  
pp. 509-516 ◽  
Author(s):  
C Zhang ◽  
M T Le ◽  
B B Seth ◽  
S Y Liang
Keyword(s):  
Operating Conditions ◽  
Accelerated Life Testing ◽  
Model Verification ◽  
Accelerated Life Test ◽  
Experimental Result ◽  
Life Testing ◽  
Accelerated Life ◽  
Bearing Life ◽  
Stress Levels ◽  
Life Tests

The reliability of a bearing is typically estabilished by repeated life testing which provides valuable information on the fatigue mechanisms from crack initiation, crack propagation to flake or spall. Under nominal operating conditions, life testing often consumes a significant amount of time and resources, due to the comparatively high bearing mean lifetime before failure (MTBF), rendering the procedures expensive and impractical. Therefore, the technology of accelerated life testing (ALT), which is widely used in manufacturing practice, offers the attractive benefit of requiring relatively less investment in terms of time and resources. Data from tests at high stress levels (e.g. temperature, voltage, pressure, corrosive media, etc.) can be extrapolated, through a physically reasonable statistical model, to obtain life estimates at lower, normal stress levels. In this study, a methodology to predict bearing lifetime under a corrosive environment has been developed based on accelerated life testing data and the application of the inverse power law. Bearing life tests under various corrosion stress levels were performed for model identification followed by additional independent bearing life tests conducted for model verification. The experimental result shows that the accelerated life test model can effectively assess the life probability of a bearing based on accelerated environmental testing, even with extrapolation to untested stress levels.

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