Influencing rolling contact fatigue through top of rail friction modifier application – A full scale wheel–rail test rig study

Wear ◽  
2011 ◽  
Vol 271 (1-2) ◽  
pp. 134-142 ◽  
Author(s):  
Richard Stock ◽  
Donald T. Eadie ◽  
Dave Elvidge ◽  
Kevin Oldknow
Wear ◽  
2008 ◽  
Vol 265 (9-10) ◽  
pp. 1222-1230 ◽  
Author(s):  
Donald T. Eadie ◽  
Dave Elvidge ◽  
Kevin Oldknow ◽  
Richard Stock ◽  
Peter Pointner ◽  
...  

1996 ◽  
Vol 118 (2) ◽  
pp. 434-442 ◽  
Author(s):  
J. R. Miner ◽  
J. Dell ◽  
A. T. Galbato ◽  
M. A. Ragen

Results of an Advanced Research Projects Agency (ARPA) sponsored project to demonstrate the operational benefits of incorporating advanced structural ceramic ball elements into the F117-PW-100 aircraft gas turbine engine high rotor thrust bearings is described. This program consists of design, fabrication, and experimental evaluation of candidate hybrid ball bearing designs in Pratt & Whitney and MRC Bearings test facilities. The bearing design criteria and development test conditions utilized for the project are compatible with the requirements of the F117-PW-100 engine system application. Two hybrid bearing designs were produced by analytically varying internal geometry features such as M-50 race curvatures and contact angles to optimize for the modulus of elasticity of the ceramic balls. CERBEC grade NBD 200 silicon nitride ceramic balls (1 1/8 in. size) demonstrated integrity and a quadruple rolling contact fatigue life improvement versus state-of-the-art M-50 steel balls in single ball test rigs. Thermal performance data obtained in full-scale bearing rig performance testing with 178 mm size hybrid and all-steel baseline bearings shows comparable characteristics. The hybrid bearing displayed a distinct survivability benefit in bearing liquid lubricant starvation testing. Two dozen hybrid bearings will be fabricated for full-scale bearing rig endurance tests to be conducted in 1995–1996 as a prerequisite to validation in operating F117-PW-100 engines in 1996–1997.


Author(s):  
Saad Ahmed Khan ◽  
Ingemar Persson ◽  
Jan Lundberg ◽  
Christer Stenström

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.


Author(s):  
Bing Wu ◽  
Boyang An ◽  
Zefeng Wen ◽  
Wenjian Wang ◽  
Tao Wu

The objective of this paper is to ascertain the wheel–rail low adhesion mechanism using a high-speed wheel–rail rolling contact test rig under different interfacial contaminations. Based on the experimental results, a numerical method was proposed to investigate the wheel–rail wear and rolling contact fatigue due to low adhesion issues. The experimental results indicated that the wheel–rail low adhesion phenomena can happen under interfacial liquid contaminations, especially at high-speed running condition. Preliminary numerical investigations showed that the low adhesion condition can easily lead to sliding hence serious wear, especially at the speed between 160 km/h and 200 km/h. The temperature rise within the contact patch can be significantly more severe once wheel and rail are in full slip, causing rolling contact fatigue due to material softening.


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