Simplification of Dynamic Capacity and Fatigue Life Estimations for Oscillating Rolling Bearings

2003 ◽  
Vol 125 (4) ◽  
pp. 868-870 ◽  
Author(s):  
John H. Rumbarger
Keyword(s):  
Fatigue Life ◽  
Load Rating ◽  
Critical Amplitude ◽  
Rolling Bearings ◽  
Text Book ◽  
Dynamic Capacity ◽  
Contact Areas ◽  
Life Data ◽  
Discrete Contact ◽  
Rolling Elements

A Dynamic capacity for oscillating rolling bearings was published in 1968 and correlated with available laboratory fatigue life data. That development of the Dynamic Capacity extended the classic fatigue life theory of Lundberg and Palmgren (1947 and 1952) to oscillating rolling bearings. The calculation of the Dynamic Capacity is simplified as a modification of present ABMA and ISO load rating and life standards for continuously rotating rolling bearings. The simplified formulas agree with the Harris, 1991, text book formulation for oscillation amplitudes (greater than the critical amplitude) which cause an overlapping of stressed contact areas by adjacent rolling elements. Oscillation amplitudes less than the critical amplitude result in separate, discrete contact areas on each raceway. Use of the Harris equations will lead to overestimation of the fatigue for oscillation amplitudes which are less than the critical amplitude.

Optimal design of radial cylindrical roller bearings for maximum load-carrying capacity

2013 ◽  
Vol 227 (11) ◽  
pp. 2393-2401 ◽  
Author(s):  
Eugenio Dragoni
Keyword(s):  
Design Procedure ◽  
Maximum Load ◽  
Geometric Optimization ◽  
Load Rating ◽  
Load Carrying Capacity ◽  
Rolling Bearings ◽  
Roller Bearings ◽  
Load Carrying ◽  
Rolling Elements ◽  
Cylindrical Roller

The design of compact and inexpensive mechanical drives and gearboxes can take advantage from the use of custom rolling bearings in which the rolling elements are directly in contact with the shaft and the housing containing them. The custom construction is particularly convenient for the case of roller bearings, either cylindrical or tapered, because these elements are easily manufactured and provide a remarkable loading capacity. Starting from the standard load rating equations available in the literature (ISO standards), this paper develops a step-by-step design procedure for the geometric optimization of radial bearings with cylindrical rollers. The procedure includes constraints on the geometry and leads to the optimal bearing with the maximum static and dynamic load ratings compatible with the space available.

Rating Life of a Linear Motion Assembly

1970 ◽  
Vol 92 (1) ◽  
pp. 34-38
Author(s):  
J. P. Hyer ◽  
T. A. Harris
Keyword(s):  
Fatigue Life ◽  
Rolling Bearing ◽  
Linear Motion ◽  
Rolling Bearings ◽  
Dynamic Capacity ◽  
Load Carrying ◽  
Analytical Development ◽  
Conventional Rolling

The linear motion assembly is a type of rolling bearing used to support and guide a translating member along a round shaftway. The load-carrying adequacy of this bearing for a given application is evaluated in the same way as for conventional rolling bearings by determining a statistical fatigue life. This paper presents an analytical development of the equations for dynamic capacity from which fatigue life can be calculated. Contact deflection and the effects of preload are also examined.

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.

Method of Calculating the Fatigue Life of Bearings Taking into Account Wearing of Rolling Elements

2020 ◽  
Vol 41 (4) ◽  
pp. 491-497
Author(s):  
V. B. Balyakin ◽  
◽  
E.P Zhilnikov ◽  
K. K Pilla ◽  
◽  
...  
Keyword(s):  
Fatigue Life ◽  
Rolling Elements

Electric impedance of rolling bearings - Consideration of unloaded rolling elements

2021 ◽  
Vol 158 ◽  
pp. 106927
Author(s):  
T. Schirra ◽  
G. Martin ◽  
S. Puchtler ◽  
E. Kirchner
Keyword(s):  
Electric Impedance ◽  
Rolling Bearings ◽  
Rolling Elements

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.

An Optimum Design of Crowned Cylindrical Roller Bearings Using Genetic Algorithms

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
K. Sunil Kumar ◽  
Rajiv Tiwari ◽  
P. V. V. N. Prasad
Keyword(s):  
Genetic Algorithms ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Stress Concentrations ◽  
Rolling Bearings ◽  
Design Constraint ◽  
Roller Bearings ◽  
Edge Stress ◽  
Heavy Loads ◽  
Cylindrical Roller

The long fatigue life is the one of the most important criterion for the design of rolling bearings, however, due to complex and diverse internal geometries, each type of rolling bearings require a different design formulation. To increase the life of cylindrical roller bearings, the profile (or the crowning) of the roller plays an important role. A flat profile of the rolling element results in the edge stress concentrations at roller ends. A circular crowning of roller eliminates the edge stress concentration at the lower and moderate loads only; however, it develops edge stress concentrations at heavy loads. The logarithmic profile of the roller results in no edge stress concentration at the low, medium, and heavy loads; distribution of contact stresses is also nearly uniform along the length of the roller. A design methodology for the optimum design of cylindrical roller bearings with the logarithmic profile has been outlined. A nonlinear constrained optimization problem has been formulated for the design of cylindrical roller bearings with logarithmic profiles and is optimized by using real-coded genetic algorithms. The change in roller profile has not been accounted for explicitly in the standard definition of the dynamic capacity; hence, for the present case directly the Lundberg–Palmgren life equation has been chosen as an objective function. Design variables include four bearing geometrical parameters and the two logarithmic profile generating parameters are considered. In addition to these, another five design constraint constants are also included, which indirectly affect the fatigue life of cylindrical roller bearings. The five design constraint constants have been given bounds based on the parametric studies through initial optimization runs. The effective length of the roller is taken corresponding to the standard roller diameter, which has standard discrete dimensions. Constraint violation study has been performed to have an assessment of the effectiveness of each of the constraints. A convergence study has been carried out to ensure the global optimum point in the design. A sensitivity analysis of various geometric design parameters has been performed using the Monte Carlo simulation technique, in order to see changes in the fatigue life of the bearing. Illustrations show that the multiplier of the logarithmic profile deviation parameter has more effect on the fatigue life as compared with other geometric parameters.

scholarly journals Bayesian estimation of the lethargy coefficient for probabilistic fatigue life model

2017 ◽  
Vol 5 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Jaehyeok Doh ◽  
Jongsoo Lee
Keyword(s):  
Fatigue Life ◽  
Sampling Method ◽  
Bayesian Updating ◽  
Unknown Parameters ◽  
Life Data ◽  
Mcmc Sampling ◽  
Fatigue Model ◽  
Relative Stress ◽  
Life Model ◽  
Static Tensile

Abstract In this study, a model for probabilistic fatigue life that is based on the Zhurkov model is suggested using stochastically and statistically estimated lethargy coefficients. The fatigue life model was derived using the Zhurkov life model, and it was deterministically validated using real fatigue life data as a reference. For this process, firstly, a lethargy coefficient that is related to the failure of materials must be obtained with rupture time and stress from a quasi-static tensile test. These experiments are performed using HS40R steel. However, the lethargy coefficient has discrepancies due to the inherent uncertainty and the variation of material properties in the experiments. The Bayesian approach was employed for estimating the lethargy coefficient of the fatigue life model using the Markov Chain Monte Carlo (MCMC) sampling method and considering its uncertainties. Once the samples are obtained, one can proceed to the posterior predictive inference of the fatigue life. This life model was shown to be reasonable when compared with experimental fatigue life data. As a result, predicted fatigue life was observed to significantly decrease in accordance with increasing relative stress conditions. Highlights Zhurkov fatigue life model is deterministically validated with experiments. Prediction of the S-N curve using Zhurkov fatigue model and lethargy coefficients. Lethargy coefficients of Zhurkov fatigue model are estimated by Bayesian updating. Bayesian updating is useful for quantifying the uncertainty of unknown parameters.

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