scholarly journals Effects of solid friction modifier on friction and rolling contact fatigue damage of wheel-rail surfaces

Friction ◽  
2021 ◽  
Author(s):  
Jingdong Song ◽  
Lubing Shi ◽  
Haohao Ding ◽  
Radovan Galas ◽  
Milan Omasta ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Rolling Stock ◽  
Friction Modifier ◽  
Railway Network ◽  
Wear Rates ◽  
Subsurface Cracks ◽  
Solid Friction

AbstractIn railway network, friction is an important factor to consider in terms of the service behaviors of wheel-rail system. The objective of this study was to investigate the effect of a solid friction modifier (FM) in a railway environment. This was achieved by studying the friction, wear, and rolling contact fatigue (RCF) damage on the wheel-rail materials at different slip ratios. The results showed that when a solid FM was applied, the friction coefficient decreased. After the solid FM was separated from the wheel-rail interface, the friction coefficient gradually increased to its original level. With the application of the solid FM, the wear rates of the wheel-rail decreased. In addition, the thickness and hardness of the plastic deformation layers of the wheel-rail materials were reduced. The worn surfaces of the wheel-rail were dominated by pits and RCF cracks. Without the FM, RCF cracks ranged from 84 to 120 µm, and subsurface cracks were generated. However, with the FM, RCF cracks ranged from 17 to 97 µm and no subsurface cracks were generated. These findings indicate possible methods of improving the performance of railway rolling stock by managing friction, and reducing wear and permanent RCF damage affecting both the wheels and rails.

scholarly journals Rolling Wear of Silicon Nitride Bearing Materials

1990 ◽  
Author(s):  
John W. Lucek
Keyword(s):  
Fatigue Life ◽  
Silicon Nitride ◽  
Failure Modes ◽  
Fatigue Testing ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wear Performance ◽  
Wear Rates ◽  
Bearing Materials

Rolling-contact fatigue test methods were used to measure the wear performance of several silicon nitride materials. Sintered, hot pressed and hot isostatically pressed materials exhibited wear rates ranging over three orders of magnitude. Hot isostatically pressed materials had the lowest wear rates. Despite the disparity in wear performance, all materials tested had useful rolling-contact fatigue lives compared to steel. Fatigue life estimates, failure modes, and rolling wear performance for theses ceramics are compared to M-50 steel. This work highlights the rapid contact stress reductions that occur due to conformal wear in rolling-contact fatigue testing. Candidate bearing materials with unacceptably high wear rates may exhibit useful fatigue lives. Rolling contact bearing materials must possess useful wear and fatigue resistance. Proper performance screening of candidate bearing materials must describe the failure mode, wear rate, and the fatigue life. Guidelines for fatigue testing methods are proposed.

Observation of Cracks of PEEK Polymer Thrust Bearings under Rolling Contact Fatigue in Water

2016 ◽  
Vol 703 ◽  
pp. 172-177 ◽  
Author(s):  
Xiao Chen Shi ◽  
Masaya Orito ◽  
Yuji Kashima ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Corrosion Resistance ◽  
Friction Coefficient ◽  
Cross Sections ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Light Weight ◽  
Low Friction ◽  
High Corrosion Resistance ◽  
Thrust Bearings

Considering the advantages on light weight, low friction coefficient, high corrosion resistance and electric insulation, polymer bearings are widely used under certain environments, where the toughness like metal bearings is not necessary. In our previous study, it was concluded that the main reason for PEEK thrust bearings failure in water was flaking due to surface crack propagation. In the present study, crack observations were made on groove surfaces and cross sections along both radial and rolling directions in order to find the relation between cracks and flaking failures.

Effect of PTFE Retainer on Friction Coefficient in Polymer Thrust Bearings under Dry Contact

2013 ◽  
Vol 683 ◽  
pp. 90-93 ◽  
Author(s):  
Koshiro Mizobe ◽  
Takashi Honda ◽  
Hitonobu Koike ◽  
Edson Costa Santos ◽  
Yuji Kashima ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Low Friction ◽  
Friction Forces ◽  
Thrust Bearings ◽  
Dry Contact

Polyetheretherketone (PEEK) is a tough semi-crystalline thermoplastic polymer with excellent mechanical properties. While abilities of polyphenylenesulfide (PPS) are similar to PEEK, former material cost was lower than later. Polytetrafluoroethylene (PTFE) is well known because of its low friction coefficient and self lubrication ability. The objective of this study is to observe the friction coefficient of hybrid bearings, PTFE retainer sandwiched with PPS-races or PEEK-races. Rolling contact fatigue tests were performed and in situ friction forces wear measured. It is concluded that the PTFE retainer reduced friction coefficient.

Research on the Approach for the Assessment of Subsurface Rolling Contact Fatigue Damage

2013 ◽  
Vol 395-396 ◽  
pp. 845-851
Author(s):  
Xiao Feng Qin ◽  
Da Le Sun ◽  
Li Yang Xie
Keyword(s):  
Shear Stress ◽  
Friction Coefficient ◽  
Fatigue Damage ◽  
Stress Ratio ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Critical Stresses ◽  
Orthogonal Shear Stress

In this paper, the distribution of different critical stresses, which were used in previous correlation articles for the assessment of subsurface rolling contact fatigue damage, was analyzed. The rationality of orthogonal shear stress was selected as the key stress controlling the subsurface rolling contact fatigue damage was clarified. Base on the linear fatigue damage accumulative theory and the modification equation for the range of asymmetrical stress, the influence of friction on subsurface rolling contact fatigue damage was studied. The results show that the subsurface orthogonal shear stress is a completely symmetrical stress when the friction coefficient is zero, while it is an asymmetrical stress with considering the friction. The stress ratio of subsurface orthogonal shear stress and subsurface rolling contact fatigue damage is increased with the increasing of friction.

Exploring the Potential for the Application of Ceramic Bearing Technology to the Wheel/Rail Interface

2007 ◽  
Author(s):  
Gerald E. Arnold
Keyword(s):  
Silicon Nitride ◽  
Wheel Running ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Future Application ◽  
Wear Rates ◽  
Steel Wheel ◽  
Rolling Elements ◽  
The Right

Ball or roller bearings have much in common with a railway wheel running on a rail. Both have high Hertzian stresses and are subject to rolling contact fatigue. Silicone Nitride (Si3N4), a Technical Ceramic, has now firmly established itself in the engineering marketplace as part of a hybrid bearing, where the rolling elements are silicone nitride and the races are steel. The paper explores the possibility of a Silicon Nitride/steel wheel/rail combination and finds that, because Silicon Nitride has a higher Modulus of Elasticity, it is not suitable as a direct replacement on existing systems, because it would produce a smaller contact patch and greater contact stress. The low toughness of Silicon Nitride in comparison to steel could be an obstacle to its general railway use, however, it could made into a composite material in the same manner as Carbon Reinforced Silicon Carbide (C/SiC) is used in brake discs. There is a possibility that, under the right conditions, Silicon Nitride could return very low wear rates, because of its extreme hardness, and because it’s excellent resistance to rolling contact fatigue (noted in hybrid bearings). This could give a wheel high mileage, without the need to remove fatigued material by controlled wear or by turning. A promising future application for the material is a cable-hauled system, where the predicted lower adhesion between Silicon Nitride and a steel rail is not a problem and the wheels are not required to be conductive.

scholarly journals Prediction of the effects of friction control on top-of-rail cracks

2016 ◽  
Vol 232 (2) ◽  
pp. 484-494 ◽  
Author(s):  
Saad Ahmed Khan ◽  
Ingemar Persson ◽  
Jan Lundberg ◽  
Christer Stenström
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Reduction Factor ◽  
Rolling Contact ◽  
Friction Modifier ◽  
Index Model ◽  
Friction Control ◽  
The North ◽  
Train Speed ◽  
Multi Body

Rolling contact fatigue is a major problem connected with railway tracks, especially in curves, since it leads to higher maintenance costs. By optimising the top-of-rail friction, the wear and cracks on the top of the rail can eventually be reduced without causing very long braking distances. There are several research articles available on crack prediction, but most of the research is focused either on rail without a friction modifier or on wheels with and without friction control. In the present study, in order to predict the formation of surface-initiated rolling contact fatigue, a range of friction coefficients with different Kalker’s reduction factors has been assumed. Kalker’s reduction factor takes care of the basic tendency of creepage as a function of the traction forces at lower creepage. The assumed range covers possible friction values from those for non-lubricated rail to those for rail with a minimum measured friction control on the top of the rail using a friction modifier. A fatigue index model based on the shakedown theory was used to predict the generation of surface-initiated rolling contact fatigue. Simulations were performed using multi-body simulation, for which inputs were taken from the Iron Ore line in the north of Sweden. The effect of friction control was studied for different curve radii, ranging from 200 m to 3000 m, and for different axle loads from 30 to 40 tonnes at a constant train speed of 60 km/h. One example of a result is that a maximum friction coefficient (µ) of 0.2 with a Kalker’s reduction factor of 15% is needed in the case of trains with a heavy axle load to avoid crack formation.

scholarly journals Codiing system for rail defects in accordance with IRS 70712

Tehnika ◽  
2021 ◽  
Vol 76 (5) ◽  
pp. 557-564
Author(s):  
Zdenka Popović ◽  
Luka Lazarević ◽  
Milica Mićić ◽  
Ljiljana Brajović
Keyword(s):  
Statistical Data ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
International Level ◽  
Railway Network

Rail defects due to the rolling contact fatigue have a significant place in the Handbook of Rail Defects in the framework of UIC Code 712 in 2002. The paper presents the system for coding and classification of rail defects according to UIC recommendation IRS 70712 in 2018. The presented classification does not cover all known defects due to the rolling contact fatigue (e.g. stud and belgrospi defects). It is recommended that Infrastructure Manager should supplement the Handbook of Rail Defects with the types of defects noticed on its railway network. The authors recommend information that should be included in the database of rail defects, in order to monitor the development of defects, taken measures and their efficiency, as well as to enable the exchange of statistical data on rail defects at the international level.

scholarly journals Dry Rolling/Sliding Wear of Bainitic Rail Steels under Different Contact Stresses and Slip Ratios

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4678
Author(s):  
Jiapeng Liu ◽  
Yingqi Li ◽  
Yinhua Zhang ◽  
Yue Hu ◽  
Lubing Shi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Contact Stress ◽  
Wear Mechanism ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wear Loss ◽  
Fatigue Wear ◽  
Slip Ratio

This study aims to deeply understand the effect of contact stress and slip ratio on wear performances of bainitic rail steels. The results showed that the wear loss increased as the contact stress and slip ratio increased. Based on the surface damage morphology and microstructural analyses, it revealed that the rolling contact fatigue wear mechanism played a significant role under the low slip ratio, but the dominant wear mechanism transferred to the abrasive wear at the high slip ratio. Meanwhile, the bainitic steel specifically presented worse wear resistance under the abrasive wear mode. Compared with the influence of a slip ratio, the increase in contact stress led to severer plastic flows and contributed to the propagation of cracks. In addition, the contact stress and slip ratio had the opposite effect on the friction coefficient, that is, the friction coefficient of bainitic steels behaved the inverse proportion with the contact stress, but positive proportion with the slip ratio. At last, the increase in slip ratio had more significant effect on the reduction of retained austenite (RA) than the enlargement of contact stress due to the fact that the RA would probably be removed before the martensitic transformation occurred under the abrasive wear mechanism.

Internal Shear Stress Distribution and Subsurface Cracks of PPS Thrust Bearings under Rolling Contact Fatigue in Water

2020 ◽  
Vol 858 ◽  
pp. 101-105
Author(s):  
Syunsuke Mizozoe ◽  
Katsuyuki Kida
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Crack Propagation ◽  
Contact Stress ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Subsurface Crack ◽  
Thrust Bearings ◽  
Subsurface Cracks

In this study, crack propagation in PPS thrust bearings under rolling contact fatigue (RCF) in water was observed, and relation between subsurface crack and internal shear stress parallel to the surface was investigated. It was found the cause of flaking was subsurface crack. They were evaluated in terms of contact stress and friction between their faces. It was discovered that subsurface cracks distributed around shear stress peak, and flaking failure was dominated by subsurface shear stress.

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