scholarly journals Study on the Steel Rail Rolling Contact Stress with Consideration of Initial Residual Stress

2015 ◽  
Vol 22 ◽  
pp. 03018 ◽  
Author(s):  
Hua Song ◽  
Jian Yang ◽  
Linbang Song ◽  
Jinkai Yao ◽  
Xinglong Du ◽  
...  
Keyword(s):  
Residual Stress ◽  
Contact Stress ◽  
Rolling Contact ◽  
Steel Rail ◽  
Initial Residual Stress

Evaluation of contact fatigue life of a wind turbine carburized gear considering gradients of mechanical properties

2018 ◽  
Vol 28 (8) ◽  
pp. 1170-1190 ◽  
Author(s):  
Wei Wang ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Zhangdong Sun
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Heavy Duty ◽  
Initial Residual Stress ◽  
Contact Fatigue Life ◽  
Carburized Gear ◽  
Load Conditions

Case hardening processes such as carburizing are extensively applied in heavy-duty gears used in wind turbines, ships, high-speed rails, etc. Contact fatigue failure occurs commonly in engineering practice, thus reduces reliabilities of those machines. Rolling contact fatigue life of a carburized gear is influenced by factors such as the gradients of mechanical properties and profile of initial residual stress. In this regard, the study of contact fatigue life of carburized gears should be conducted with the consideration of those aspects. In this study, a finite element elastic–plastic contact model of a carburized gear is developed which takes the gradients of hardness and initial residual stress into account. Initial residual stress distribution and the hardness profile along the depth are obtained through experimental measurements. The effect of the hardness gradient is reflected by the gradients of yield strength and fatigue parameters. The modified Fatemi–Socie strain-life criterion is used to estimate the rolling contact fatigue life of the heavy-duty carburized gear. Numerical results reveal that according to the Fatemi–Socie fatigue life criterion, rolling contact fatigue failure of the carburized gear will first initiate at subsurface rather than surface. Compared with the un-carburized gear, the rolling contact fatigue lives of the carburized gear under all load conditions are significantly improved. Under heavy load conditions, the carburized layer significantly reduces the fatigue damage mainly due to the benefit to inhibit the accumulation of plasticity. Influence of the residual stress is also investigated. Under the nominal load condition, compared with the residual stress-free case, the existence of the tensile residual stress causes remarkable deterioration of the rolling contact fatigue life while the compressive residual stress with the same magnitude leads to a moderate growth of the rolling contact fatigue life. As the load becomes heavier when plasticity becomes notable, the influence of the initial residual stress on the life is somewhat weakened.

Variation in Residual Stress Field During Fatigue Failure of Thermal Spray Coatings

2000 ◽  
Author(s):  
R. Ahmed ◽  
M. Hadfield ◽  
S. Tobe
Keyword(s):  
Residual Stress ◽  
Thermal Spray ◽  
Fatigue Failure ◽  
Contact Stress ◽  
Rolling Direction ◽  
Rolling Contact ◽  
Thermal Spray Coatings ◽  
Residual Stress Field ◽  
Stress Measurements ◽  
Spray Coatings

Abstract A non-destructive experimental approach was adapted to investigate the variations in residual stress fields within thermal spray coatings. WC-Co coatings produced by a HVOF technique were considered for concentrated rolling sliding contacts in this study. These coatings were produced in various thicknesses on various substrates. Residual stress measurements were made using an x-ray diffraction technique, along and across the rolling direction. A modified four-ball machine was used to conduct rolling contact fatigue tests under various tribological conditions of contact stress, lubrication and contact configuration. Residual stress measurements were made before and after the tribological tests. Failed rolling elements were analyzed using scanning electron microscopy, electron probe microscopy and surface interferometry. Results indicate that the magnitude of compressive residual stress attenuates during fatigue failure. The magnitude of attenuated residual stress was dependent upon the type of tribological failure. This attenuation of residual stress was attributed to the microcracking of coating under the influence of contact stress.

Influence of Initial Residual Stress on Material Properties of Bearing Steel During Rolling Contact Fatigue

2014 ◽  
Vol 57 (3) ◽  
pp. 533-545 ◽  
Author(s):  
Bryan Allison ◽  
Ghatu Subhash ◽  
Nagaraj Arakere ◽  
David A. Haluck ◽  
Herb Chin
Keyword(s):  
Residual Stress ◽  
Material Properties ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Initial Residual Stress

Evaluation of Rolling Contact Fatigue of a Carburized Wind Turbine Gear Considering the Residual Stress and Hardness Gradient

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Wei Wang ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Philippe Bocher ◽  
Heli Liu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Residual Stress Distribution ◽  
Rolling Contact ◽  
Material Strength ◽  
Initial Residual Stress ◽  
Failure Risk ◽  
Local Material

Carburized gears are applied extensively in large-scale heavy duty machines such as wind turbines. The carburizing and quenching processes not only introduce variations of hardness from the case to the core but also generate a residual stress distribution, both of which affect the rolling contact fatigue (RCF) during repeated gear meshing. The influence of residual stress distribution on the RCF risk of a carburized wind turbine gear is investigated in the present work. The concept of RCF failure risk is defined by combining the local material strength and the multi-axial stress condition resulting from the contact. The Dang Van multi-axial fatigue criterion is applied. The applied stress field is calculated through an elastic-plastic contact finite element model. Residual stress distribution and the hardness profile are measured and compared with existed empirical formula. Based upon the Pavlina–Tyne relationship between the hardness and the yield strength, the gradient of the local material strength is considered in the calculation of the RCF failure risk. Effects of the initial residual stress peak value and its corresponding depth position are studied. Numerical results reveal that compressive residual stress (CRS) is beneficial to RCF fatigue life while tensile residual stress (TRS) increases the RCF failure risk. Under heavy load conditions where plasticity occurs, the accumulation of the plastic strain within the substrate is significantly affected by the initial residual stress distribution.

Determination of Rolling Contact Stress Distribution by X-ray Diffraction

1989 ◽  
Vol 33 ◽  
pp. 341-352
Author(s):  
David L. Milan
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Contact Stress ◽  
Rolling Direction ◽  
Roller Bearing ◽  
Rolling Contact ◽  
Outer Race ◽  
Contact Stress Distribution ◽  
Inner Race

AbstractAn investigation was conducted of the potential for detection of the contact stress distribution in tapered roller bearing components made of carburized steel. Various raceway stress distributions were created by control of the profile and alignment of the rolling surfaces. Determination of residual stress in the rolling direction and peak breadth were made using a multiple tilt sin2 ψ technique. The measurements were made at the surface and at depths below the surface. It was found that the distribution of residual stress and peak breadth perpendicular to the rolling direction in the layers below the surface of the inner race correlated highly with the imposed contact stress distribution. The correlation was less in the case of the outer race. The residual stress distribution measured on the surface of the inner race was observed to be inversely proportional to the contact stress distribution.

Residual Stress Change Due to Rolling Contact of Ball and Roller Bearings

1980 ◽  
Vol 24 ◽  
pp. 215-220
Author(s):  
Kikuo Maeda ◽  
Noriyuki Tsushima ◽  
Hiroshi Muro
Keyword(s):  
Residual Stress ◽  
Contact Stress ◽  
Stress Measurement ◽  
Rolling Bearing ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Compressive Yield Strength ◽  
Rolling Elements ◽  
Hertzian Contact Stress

The life of a rolling bearing is predominantly determined by the contact stress between the rolling elements (ball and roller) and the raceway of inner and outer rings. The contact stress is calculated by assuming Hertzian stress distribution. The maximum Hertzian contact stress Pmax usually ranges from 2000 to 3000 MPa in actual service of rolling bearings. These figures are rather large compared to the compressive yield strength of hardened bearing steel (σys = 2000 MPa). Therefore plastic deformation sometimes occurs under the raceway, creating residual compressive stress. Several investigators have so far reported about the residual stress due to rolling contact. There were, however, few who referred to the residual stress in used bearings and application of residual stress measurement to failure analysis.

Service Loading Analysis of Wind Turbine Gearbox Rolling Bearings Based on X-Ray Diffraction Residual Stress Measurements

2013 ◽  
Vol 768-769 ◽  
pp. 723-732 ◽  
Author(s):  
Jürgen Gegner ◽  
Wolfgang Nierlich
Keyword(s):  
Residual Stress ◽  
Wind Turbine ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
X Ray Diffraction ◽  
Rolling Bearings ◽  
Wind Turbine Gearbox ◽  
X Ray ◽  
Stress Measurements

Rolling bearings in wind turbine gearboxes occasionally fail prematurely by so-called white etching cracks. The appearance of the damage indicates brittle spontaneous tensile stress induced surface cracking followed by corrosion fatigue driven crack growth. An X-ray diffraction based residual stress analysis reveals vibrations in service as the root cause. The occurrence of high local friction coefficients in the rolling contact is described by a tribological model. Depth profiles of the equivalent shear and normal stresses are compared with residual stress patterns and a relevant fracture strength, respectively. White etching crack failures are reproduced on a rolling contact fatigue test rig under increased mixed friction. Causative vibration loading is evident from residual stress measurements. Cold working compressive residual stresses are an effective countermeasure.

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