Bearing Fatigue Life Research Articles

Analysis of Rolling Contact Bearings Test Data by the Bımodal Method

Lieblein J. and Zelen A. conducted a study of the fatigue life of deep groove ball bearings. This study was based on data of 4948 bearings as obtained from 5 companies and 213 test groups. Among these data is a detailed test report #3183, lot 73, consisting of 23 failed bearings. This report states that the Weibull slope of this group is 2.23, meaning that this distribution is mono sloped. These test data were plotted by the author on a bilinear scale plane, of endurance life versus bearing number and proved to be distinctly bi sloped. This basic difference prompted a wide study resulting in several new findings and set the grounds for a new analysis method.

Monitoring of bearing fatigue life based on hidden Markov model

With the increase in the intelligence of the production process and the increase in reliability requirements, the monitoring of the bearing life status after the event has been unable to meet the needs of industrial production. Performance degradation assessment and life monitoring have attracted more attention as intelligent methods based on condition maintenance. Hidden Markov model is a statistical probability model based on time series, which is very suitable for modeling the performance degradation process of equipment. Therefore, this paper proposes a life monitoring algorithm based on hidden Markov model. First, the continuous wavelet transform is introduced to obtain the optimal value of the shape factor or the stretch factor. Secondly, a hidden Markov model of multi-channel information fusion is proposed. The algorithm significantly improves the effectiveness and robustness of life monitoring. The hidden Markov model explicitly expresses the state duration distribution, making the model more suitable for life monitoring.

An improved energy prediction method to predict the fatigue life of laminated rubber-alloy spherical thrust elastomeric bearing under multiaxial loads

PurposeAn ideal method for predicting the fatigue life of spherical thrust elastomeric bearings has not been reported, thus far. This paper aims to present a method for predicting the fatigue life of laminated rubber spherical thrust elastomeric bearings.Design/methodology/approachFirst, the mechanical properties of standard rubber samples were tested; the axial stiffness, cocking stiffness, torsional stiffness and fatigue life of several full-size spherical thrust elastomeric bearings were tested. Then, the stiffness results were calculated using the neo-Hookean, Mooney–Rivlin and Yoeh models. Using a modified Mooney–Rivlin constitutive model, this paper proposes an improved method for fatigue life prediction, which considers the laminated characteristics of a spherical thrust elastomeric bearing and loads of multiple multi-axle conditions.FindingsThe Mooney–Rivlin model could accurately describe the stiffness characteristics of the spherical thrust elastomeric bearings. A comparative analysis of experimental results shows that the model can effectively predict the life of a spherical thrust elastomeric bearing within its range of use and the prediction error is within 20%.Originality/valueThe fatigue parameters of elastomeric bearings under multiaxial loads were fitted and corrected using experimental data and an accurate and effective multiaxial fatigue-life prediction expression was obtained. Finally, the software was redeveloped to improve the flexibility and efficiency of modeling and calculation.

The effect of the uncertain initial angular misalignment on fatigue life of spindle-bearing system

The initial angular misalignment due to mounting error is unavoidable and uncertain during the application of rolling element bearings. The effects of the uncertainty of the initial angular misalignment on fatigue life of angular contact ball bearings and spindle system are investigated. To achieve this, the contact forces of ball bearings in spindle system are analyzed based on the system model considering initial angular misalignment and spindle speed. Two initial angular misalignment cases are taken into account, and the angular misalignment sample is extracted for each case by Monte carlo sampling method. The fatigue life results for each ball bearing are obtained. The results show that the uncertain initial angular misalignment can lead to the rating life dispersion of ball bearings and the degree of rating life dispersion is related to the angular misalignment case and spindle speed. Based on the reliability theory of series system, the spindle system rating life is obtained, the probability density distribution and cumulative distribution are both presented. The results show that two angular misalignment cases produce significantly different effects to the rating life and fatigue life distribution of spindle system.

Axial Load Capacity and Stresses in Combined Loaded Radial Ball Bearings (Dept.M)

An interactive and easy to use simulation tool has been developed to simulate and depict normal loads, contact angle, normal deformations, and stresses at any angular position of the rolling element for combined loaded radial ball bearings. The importance of this work comes from the ability to determine the contact angle and induced normal toad at any angular position. The main objective of this work is to lower stresses within the bearings, consequently, bearing fatigue life which is governed by stress level is significantly affected, showing that the lower the stress level the higher the service lifetime. This work is intended to serve both design and maintenance engineers.

Strength Against Fracture of End Hemispherical Cavity Roller Under Static Loading: Experimental and Simulation Investigation

Abstract Enhancement in fatigue life of the rolling-element bearing has been captivating since years. The hollow concept had been triggered years back; however, it could not catch widespread applications due to catastrophic failure. Thus, any novel concept of the rolling element must be assessed for its strength against catastrophic failure before competing for better fatigue life on field with other alternatives. This paper commences with the outcomes of the comparative assessment of the experimental evaluation of strength against fracture under static loads for layered and hollow rollers with solid rollers, which devise the requirements for new concepts. The end hemispherical cavity (EHC) roller concept, being a proper geometrical blending of solidity and hollowness, prospects to overcome the strength concern along with a considerable reduction in contact stresses. Thus, experimental investigation was conducted with full-bearing fracture tests and individual roller specimens fracture tests for five variants: EHC, solid, layered, 61H, and 37H (hollow rollers with 61% and 37% hollowness, respectively). The simulations were carried out to support the outcomes of experimental trials. The experimental results with full-bearing samples and individual roller specimens demonstrated ranking as follows: EHC, 37H, layered, and 61H. The EHC roller concept was substantiated to be stronger than hollow and layered rollers besides prompting appreciable reduction in contact stresses compared with the solid roller. The simulation results agreed well with experimental results of fracture tests, and the recommendations from findings of failure theories (maximum normal stress, distortion energy, and maximum shear stress) adopted for estimating fracture load for rollers have been discussed.

Lubrication and Fatigue Life Evaluation of High-Speed Cylindrical Roller Bearing under Misalignment

This paper developed a coupled model, incorporating the quasistatic model, fatigue life model, and mixed lubrication model, to investigate the effect of misalignment angle on high-speed cylindrical roller bearings. The model is verified by comparing with the published literature results. Then, a parametric analysis is carried out. The results show that as the misalignment increases, the load distribution is basically unchanged, but the fatigue life of the roller bearing decreases due to the variation of contact pressure, and the skewing moment of single roller contact pair increases. Furthermore, the optimal design of roller profile needs to consider the effect of lubrication in order to improve the fatigue life of roller bearings. In general, the optimal crown drop is too small according to the design from the slicing technique.

Failure Analysis of Ball Bearing of Conveyor: Overusage

Rolling bearings are machine elements found in a wide field of applications. They are reliable even under the toughest conditions. When bearings fail to meet their expected life, the consequences are increased down time, loss of revenue and missed delivery. Hence, it is important to know the bearing theoretical fatigue life. However, unfortunately, it sometimes happens that a bearing does not attain its calculated rating life. There may be many reasons for this—heavier loading than has been anticipated, inadequate or unsuitable lubrication, careless handling, ineffective sealing, improper mounting and improper clearance. This article describes the failure of a conveyor bearing in rolling contact fatigue. The investigation consists of visual observation, chemical analysis, characterization of microstructures using optical microscopes and hardness test. The study also calculates the bearing fatigue life (L10) under these operating conditions. Surface-initiated rolling contact fatigue, leading to spalling, is a life-limiting failure mode in bearings. Ferrography test, discussed in this paper, indicates fatigue spalling. Analysis suggested that the conveyor bearing failed near its calculated fatigue life and the failure occurred in rolling contact fatigue. Periodic schedule, after calculating L10 life, for changing the bearing and scheduled ferrography checks can eliminate this type of unplanned breakdown.

Kinematic investigation and fatigue life analysis of angular contact ball bearing in wide speed range based on raceway friction

PurposeThe purpose of this paper is to clarify the relationship between fatigue life and kinematics of angular contact ball bearing. It proposes a new modeling method of spin to roll ratio based on raceway friction, which is more accurate than the traditional raceway control theory.Design/methodology/approachThe uniform model of spin to roll ratio based on raceway friction in a wide speed range is proposed using quasi-statics method, which considers centrifugal force, gyroscopic moment, friction force of raceway and other influencing factors. The accuracy is considerably improved compared with the static model without increasing too much computation.FindingsA uniform model for spin to roll ratio of angular contact ball bearing based on raceway friction is established, and quite different relationships between fatigue life and speed under two operating conditions are found.Research limitations/implicationsThe conclusion of this paper is based on the bearing basic fatigue life calculation theory provided by ISO/TS 16281; however, the accuracy of theory needs to be further verified.Practical implicationsThis paper provides guidance for applying angular contact ball bearing, especially at a high speed.Originality/valueThis paper reveals the changing trend of fatigue life of angular contact ball bearing with the speed under different loads.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0030

Fatigue life evaluation of spindle of rolling mill using ADINA structure and WINLIFE

The fatigue life prediction method using numerical analysis is the latest evaluation technology to predict the fatigue life using the stress data obtained from the structural analysis in order to reduce the evaluation time and cost. A rolling mill is a machine that produces a coil by rolling the material by a roller and the spindle of the rolling mill device serves to transmit the power to the rollers by periodically rotating by the motor. These spindles consist of universal joints, shafts and bearings to deliver power to the rollers. The spindle of the rolling mill is always exposed to the environment subjected to the fatigue load due to the rotation moment by the periodic rotation and there is possibility of the breakage accident due to this. It is very important to prevent breakage by predicting the fatigue life of the spindle in a dynamic operating environment. Therefore, in this study, dynamic stress analysis is performed considering the actual rotating environment conditions using ADINA. Based on the results of stress analysis, we want to predict fatigue life considering dynamic operating environment using WINLIFE that is used for the evaluation of the fatigue life of single shafts, multi-shafts, and gear bearings. Fatigue life analysis of the spindle of the rolling mill using linear cumulative damage theory using S-N curve and equivalent stress was performed in order to evaluate the fatigue life. Stress-life fatigue theory is a method of calculating the lifetime by the minimum input showing the fatigue characteristics of the material.

A model for rolling bearing life with surface and subsurface survival: Surface thermal effects

A previously developed model for bearing life calculation, based on high-cycle fatigue, including the separation of the surface and the subsurface survival of the rolling contact, is herewith further extended. It now includes the effects of frictional heating with a sharp temperature rise developed in the rolling contact. For this, a new surface damage integral, based on the creep mechanism, is included in the model. With this modification, the detrimental effect of high temperature developed in the rolling contact can now be accounted for. Sharp surface temperature rise during over-rolling are found in bearings operating at high speeds or under the combination of speeds, loads and unfavourable environmental temperatures. The present model introduces a threshold limit value of temperature above which the temperature in the rolling contact is deemed damaging for the steel microstructure and the tribological functionality of the rolling contact. The surface creep-damage model is first calibrated with endurance tests of bearings and then applied to study combinations of loads and speeds and the effect of the steel thermal conductivity on the life expectancy of the bearing. The ability of the present model to include damaging mechanisms, other than classical metal fatigue, increases the flexibility in bearing life predictions and allows to account for phenomena hitherto excluded from the estimation of the bearing fatigue life.

Research on the rolling contact fatigue life of the bearing considering the friction effect

In this paper, a theoretical model is proposed to analyze the friction effect on the rolling contact fatigue (RCF) life of the angular contact ball bearing (ACBB). Firstly, the quasi-static model without race control hypothesis is introduced to study the load characteristics of the ACBB under different loading conditions. Then, the friction coefficient is quantitatively calculated by analyzing the relation between the gyroscopic torque and the sphere-race contact load. The effects of the axial load, radial load, torque load and rotating speeds on the friction coefficient, the maximum value of the sub-surface von Mises stress (SSVS) and the maximum peak-peak value of the sub-surface shear stress (SSSS) are subsequently investigated. The results show that they can significantly affect the friction coefficient and further influence the stress field beneath the contact surface. Further studies illustrate that the friction coefficient cannot affect the maximum peak-peak value of the SSSS but can change the distribution of the SSVS field. The relative RCF life of the sphere-race contact is calculated and the published studies confirm the accuracy of the calculation.

Influence of angular misalignment on the tribological performance of high-speed micro ball bearings considering full multibody interactions

To study the angular misalignment effects on the high-speed micro ball bearing which is applied to the dental handpiece, an improved five-degree-of-freedom quasi-dynamic model considering full multibody interactions is established in this paper. Then the modified fatigue life model presented by Jones is adopted to further evaluate the influence of angular misalignment on the reliability of the bearing. The results show that the angular misalignment significantly influences the contact load and contact angle distributions as well as the skidding behavior under both pure axial load and combined axial and radial loads. After comprehensive comparison, it is found that the impacts of angular misalignment on total power loss and bearing fatigue life are different under the two types of loads. Under pure axial load, the total power loss increases consistently and the bearing fatigue life decreases significantly when the absolute value of angular misalignment becomes larger. However, under combined axial and radial loads, the effects of angular misalignment are rather complicated and the direction of angular misalignment turns out to be a key influencing factor.

The Effect of Waviness Error on the Power Loss of the Planet Bearing

The power loss of planet bearings can affect the energy efficiency of planetary gear transmission systems. Although many works studied the power loss of various planet bearings, the effect of the waviness error on the power loss of the planet bearings was missed. To overcome this problem, an analytical model of the power loss of a planet bearing with the waviness error is proposed. The power loss of the planet bearing caused by the elastic material hysteresis, differential slipping, and lubricating oil viscosity is considered in this model. The results from the proposed model and experiment in the reference are compared to show the model validation. The effects of the pinion bore diameter, input speed, external moment, waviness amplitude, and waviness order on the power loss of the planet bearing are analyzed. It shows that this study can give a useful method to predict the power loss of the planet bearing with and without the waviness error. Moreover, the results can also give some guidance to reduce the power loss and improve the fatigue life of the planet roller bearings.

МЕТОДИКА РАСЧЕТА ДОЛГОВЕЧНОСТИ ПОДШИПНИКОВ С УЧЁТОМ ИЗНОСА ТЕЛ КАЧЕНИЯ

МЕТОДИКА РАСЧЕТА ДОЛГОВЕЧНОСТИ ПОДШИПНИКОВ С УЧЁТОМ ИЗНОСА ТЕЛ КАЧЕНИЯ

Effects of Bearing Locations on the Characteristics of a Spindle System Supported by Tapered Roller Bearings

This paper presents the effects of bearing locations on the mechanical characteristics of a multi-stepped spindle system related to bearing fatigue life, natural frequency, and static stiffness. The multi-stepped spindle is supported by a pair of tapered roller bearings (TRBs) and subjected to radial loading. To solve the equilibrium equation of the spindle system which is inherently statically-indeterminate, this study adopts an integrated shaft-bearing model, where the spindle is modelled by the finite shaft elements and the supporting TRBs are modelled by the five degrees-of-freedom TRB model developed by the authors. An iterative computational method is used to estimate the spindle deflection coupled with bearing deflections, and afterwards the bearing stiffness and internal contact loads of rolling elements are computed. The bearing fatigue life based on the ISO standard and the first natural frequency of the spindle system are evaluated with the spindle-bearing model. The influences of bearing locations on the static stiffness and natural frequency of the spindle, and the fatigue life of TRBs are rigorously investigated. The numerical results show the noticeable effects of bearing locations on the spindle system characteristics. The presented results provide a comprehensive assessment to aid for design optimization of spindle-TRB system.

Studies on the Influence of Residual Stresses on the Fatigue Life of Rolling Bearings in Dependence on the Production Processes

The production process significantly influences the surface properties of rolling element bearings raceways. Deep rolling can induce a depth dependent residual stress state. Previous numerical and experimental studies have shown that rolling bearings fatigue life can be positively influenced by high compressive residual stress to a depth of around 300 µm from the surface. By extending the components life, the resource efficiency of machine components can be increased. In order to determine the influence of the residual stress state in bearing fatigue life, a calculation method was developed for predicting the bearing fatigue life. This method was validated for hard-turning and subsequent deep rolling by experiments on a test rig in four-bearing configuration under radial load. An increase of the L10 bearing life by a factor of 2.5 has been achieved by inducing residual stresses on the bearing’s inner ring. Due to similar process control, the manufacturing steps turning and deep rolling were combined. Bearings were manufactured combining the processes hard-turning and deep rolling (called turn-rolling). The heat from the hard machining has an effect on the residual stresses in the bearing subsurface, thus further altering the magnitude and maximum depth of the residual stress influencing the microstructure. With these bearings, the additional fatigue life was determined experimentally and compared to the results of the bearings produced by hard-turning and subsequent deep rolling. It could be shown, that the process of hard turning and subsequent deep rolling has highest potential to achieve improved bearing fatigue life. These findings were transferred to a “Tailored Forming” shaft with integrated raceway in a second step. In this case, a shaft made of mild steel is combined with a cladding layer of high strength bearing steel to be used as a bearing raceway.

A method to model crystalline anisotropy in contact using semi-analytical method

In this paper, the contact problem between a cylinder and a half-space with a crystalline anisotropic behavior is solved. The model is based on semi-analytical methods to solve a three dimensional contact problem. A numerical technique based on a Voronoi tessellation is implemented using the Eshelby's equivalent inclusion method to account for the effect of the material microstructure on the contact pressure distribution and subsurface stresses. Fast Fourier Transforms (3D and 2D) are used to reduce the computation cost of the simulations. An application of this method to compute the scatter in fatigue life of rolling element bearings is also presented. Three different critical stresses are used in the Lundberg-Palmgren equation and results are compared in term of Weibull plot slope.

Failure Life Prediction of Hub Bearing in Composite Tooling

Composite work tools have many components, and complex shapes when compared to standard tools such as rotaries and plows. In addition, the component durability for the tools is critical because the load varies severely according to the soil conditions. This study predicts the fatigue life of the hub bearing in composite work tooling. The loads acting on the tools were measured based on field tests, and the loads acting on the hub bearing were derived using the load reconstruction method. The static safety factor and fatigue life of the hub bearing, loads, and contact stress acting on the inner and outer raceways and presence of truncation were analytically predicted based on the derived loads. The fatigue life of the bearing changed depending on the preload amount of the hub bearing. The bearing life was more than 3000 h for preloads of less than 40 μm, which satisfied the target life of 1200 h. The load acting on the inner and outer raceways of the bearing decreased and then increased as the preload amount of the bearing rose. The bearing contact area, maximum contact stress, and number of balls increased as the load applied to the hub bearing rose. The fatigue life, load, contact stress, and static safety factor of the hub bearing met all requirements, and no truncation occurred on the inner and outer raceways of the bearing. The test verified the achievement of the target life of 1200 h and confirmed that there was no breakage, cracking, or deformation of the bearing.

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

Experimental data on the wear of rolling elements are used to develop a method developed for determining the fatigue life of rolling bearings taking into account their wear. The results of calculating the fatigue life of a bearing taking into account the wear of rolling elements are given. It is shown that wear of rolling elements reduces the fatigue life of bearings.