scholarly journals Experimental Study of Effects of the Third Medium on the Maximum Friction Coefficient between Wheel and Rail for High-Speed Trains

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
He Ma ◽  
Yan Niu ◽  
Xiaochun Zou ◽  
Jun Zhang
Keyword(s):  
Friction Coefficient ◽  
Quartz Sand ◽  
High Speed ◽  
Static Friction ◽  
Test Bed ◽  
Maximum Friction ◽  
Contact Test ◽  
Influence Of Water ◽  
High Speed Trains ◽  
Fallen Leaves

The changes of the friction coefficient between wheel and rail affect the wheel-rail adhesion characteristics of high-speed trains. The adhesion state in the wheel-rail contact area could be distinguished by the maximum friction coefficient between wheel and rail. The wheel-rail adhesion is of great significance for high-speed train traction. In order to study the influence of water, oil, fallen leaves, quartz sand, or their mixtures on the maximum friction coefficient between high-speed wheel and rail, a wheel-rail contact test bed is built to carry out the wheel-rail contact test and wheel-rail friction contact test. The comparative analysis of the test results shows that the axle load has little influence on the maximum friction coefficient between wheel and rail. Water, oil, and fallen leaves would reduce the maximum friction coefficient. Quartz sand could increase the maximum friction coefficient in a short time, while the excessive static friction coefficient would damage the wheel and rail. Besides, the maximum friction coefficient of water, oil, and fallen leaves mixing in pairs is lower than each of them existing alone. Both water and oil could increase the adhesion of quartz sand, and the effect of water is better. Therefore, when the sand still could not meet enough traction, it could be considered to add some water to increase the wheel-rail adhesion.

A Model for Contact and Static Friction of Nominally Flat Rough Surfaces Under Full Stick Contact Condition

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
D. Cohen ◽  
Y. Kligerman ◽  
I. Etsion
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Friction Force ◽  
Contact Area ◽  
Rough Surfaces ◽  
Normal Load ◽  
Static Friction ◽  
Contact Condition ◽  
Maximum Friction ◽  
Static Friction Coefficient

A model for elastic-plastic nominally flat contacting rough surfaces under combined normal and tangential loading with full stick contact condition is presented. The model incorporates an accurate finite element analysis for contact and sliding inception of a single elastic-plastic asperity in a statistical representation of surface roughness. It includes the effect of junction growth and treats the sliding inception as a failure mechanism, which is characterized by loss of tangential stiffness. A comparison between the present model and a previously published friction model shows that the latter severely underestimates the maximum friction force by up to three orders of magnitude. Strong effects of the normal load, nominal contact area, mechanical properties, and surface roughness on the static friction coefficient are found, in breach of the classical laws of friction. Empirical equations for the maximum friction force, static friction coefficient, real contact area due to the normal load alone and at sliding inception as functions of the normal load, material properties, and surface roughness are presented and compared with some limited available experimental results.

Effect of different contact surfaces between concrete sleeper and ballast on mobilized lateral resistance against impact loads

2016 ◽  
Vol 231 (6) ◽  
pp. 678-689 ◽  
Author(s):  
Ahmad Hosseini ◽  
Morteza Esmaeili
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Static Friction ◽  
Railway Track ◽  
Rolling Stock ◽  
Lateral Impact ◽  
Loading Test ◽  
Analysis And Design ◽  
Dynamic Friction Coefficient ◽  
Lateral Resistance

The amount of ballast particles surrounding a railway track significantly influences its resistance in all directions. As time goes by, with the development of high-speed trains, more attention has been paid to this issue owing to the increase in dynamic effects of rolling stock on track loading. The focus of the present study is on the investigation of the interaction between different surfaces (base, crib, and shoulder) of concrete sleeper and their adjacent ballast layer along with the related parameters under lateral impact loading condition. In this regard, by utilizing a pendulum loading test device, a number of lateral impact tests were conducted on an instrumented concrete sleeper in laboratory. On the basis of experimental results, the average contribution of base, crib, and shoulder zones in the total dynamic lateral resistance of sleeper was calculated as 48%, 23%, and 29%, respectively. Furthermore, in the lateral impact force domain of 13–28 kN, the sleeper–ballast dynamic friction coefficient at base and crib zones varied in the ranges 0.8–1.5 and 0.5–0.6. Moreover, a maximum impact factor of 2.5 was obtained for analysis and design purposes. It should be stated that the trend of laboratory results confirmed the common static friction coefficient of 0.8.

Battery Self-Traction System for High-Speed Trains

2020 ◽  
Vol 140 (5) ◽  
pp. 349-355
Author(s):  
Hirokazu Kato ◽  
Kenji Sato
Keyword(s):  
High Speed ◽  
High Speed Trains ◽  
Traction System

Development of Magnesium Alloys for High Speed Trains in China

2016 ◽  
pp. 7-8
Author(s):  
Eric Nyberg ◽  
Jian Peng ◽  
Neale R. Neelameggham
Keyword(s):  
Magnesium Alloys ◽  
High Speed ◽  
High Speed Trains

Iterative Learning Operation Control of High-Speed Trains With Adhesion Dynamics

2021 ◽  
pp. 1-11
Author(s):  
Deqing Huang ◽  
Wanqiu Yang ◽  
Tengfei Huang ◽  
Na Qin ◽  
Yong Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Iterative Learning ◽  
High Speed Trains ◽  
Operation Control
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