Some Features and Metallurgical Considerations of Surface Defects In Rail Due to Contact Fatigue

2009 ◽  
pp. 233-233-23 ◽  
Author(s):  
H Masumoto ◽  
K Sugino ◽  
S Nisida ◽  
R Kurihara ◽  
S Matsuyama
Keyword(s):  
Surface Defects ◽  
Contact Fatigue

A Coupled Multibody Finite Element Model for Investigating Effects of Surface Defects on Rolling Contact Fatigue

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Zamzam Golmohammadi ◽  
Farshid Sadeghi
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Surface Defects ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Internal Stresses ◽  
Fe Model ◽  
Elastic Plastic ◽  
Pile Up

A coupled multibody elastic–plastic finite element (FE) model was developed to investigate the effects of surface defects, such as dents on rolling contact fatigue (RCF). The coupled Voronoi FE model was used to determine the contact pressure acting over the surface defect, internal stresses, damage, etc. In order to determine the shape of a dent and material pile up during the over rolling process, a rigid indenter was pressed against an elastic plastic semi-infinite domain. Continuum damage mechanics (CDM) was used to account for material degradation during RCF. Using CDM, spall initiation and propagation in a line contact was modeled and investigated. A parametric study using the model was performed to examine the effects of dent sharpness, pile up ratio, and applied load on the spall formation and fatigue life. The spall patterns were found to be consistent with experimental observations from the open literature. Moreover, the results demonstrated that the dent shape and sharpness had a significant effect on pressure and thus fatigue life. Higher dent sharpness ratios significantly reduced the fatigue life.

Evaluation of Surface Defects of Wheel and Rail for Korean High-Speed Railway

2010 ◽  
Vol 654-656 ◽  
pp. 2499-2502 ◽  
Author(s):  
Chan Woo Lee ◽  
Seok Jin Kwon
Keyword(s):  
High Speed ◽  
Surface Defects ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Railway Vehicle ◽  
High Speed Railway ◽  
Main Research ◽  
Rail Systems ◽  
Micro Cracks

Wheels of the railway vehicle play the important role for driving train through wheel-rail interaction. Especially wheel profile is one of the most important design factors to rule the running stability and safety of train. Accordingly, the control of rolling contact fatigue-related defects is an ongoing concern for both safety and cost reasons. This process is referred to as ratcheting. Wear of wheel and rail surfaces occur due to a mixture of adhesive, abrasive and corrosive processes. In wheel/rail systems with little wear, such failure is manifested by the appearance of closely spaced micro-cracks. In the present paper, a evaluation of surface defects of wheel and rail for Korean high-speed railway. The main research application is the wheel-rail maintenance of Korea high-speed train.

scholarly journals Experimental Investigations to Analyze Surface Contact Fatigue Wear by Using a Dynamic Response of the Roller Bearing System

2021 ◽  
Author(s):  
Shashikant Pandey ◽  
Amarnath Muniyappa
Keyword(s):  
Surface Defects ◽  
Roller Bearing ◽  
Contact Fatigue ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Fatigue Wear ◽  
Lubrication Regimes ◽  
Promising Tool ◽  
Bearing Contact ◽  
Contact Surfaces

Abstract Bearings are used to reduce friction between two rolling /sliding members of the machines. Under normal operating conditions, an increase in the fatigue load cycles on the bearing contact surfaces results in surface defects viz. micro pitting, macro pitting, spalling and scuffing, thereby causing lubricant degradation. Hence, to maintain a better operating performance of rotating machines, it is essential to keep track of operating parameters. This paper describes the results of experimental investigations carried out to assess wear propagation on bearing contact surfaces using tribological and vibration parameters. Results obtained from experimental investigations provide a good correlation between the increase in surface fatigue wear and corresponding effects on transition in lubrication regimes, increased vibration levels, variations in rheological properties of lubricant and wear mechanisms developed on the contact surfaces of the roller bearing. The proposed approach can be used as a promising tool to assess incipient faults developed in roller bearing.

scholarly journals Effects of surface defects on rolling contact fatigue of 60/40 brass

Wear ◽  
1999 ◽  
Vol 225-229 ◽  
pp. 983-994 ◽  
Author(s):  
N. Gao ◽  
R.S. Dwyer-Joyce ◽  
J.H. Beynon
Keyword(s):  
Surface Defects ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact

The statistical characteristics of the rail steel wear in conditions of fretting-fatigue

2018 ◽  
Vol 84 (11) ◽  
pp. 70-73
Author(s):  
E. M. Morozov ◽  
A. P. Soldatenkov
Keyword(s):  
Wear Resistance ◽  
Cyclic Loading ◽  
Surface Defects ◽  
Rail Steel ◽  
Contact Fatigue ◽  
Statistical Processing ◽  
Quantitative Measure ◽  
Fretting Fatigue ◽  
Statistical Characteristics ◽  
Contact Wear

A method of processing the results of tests for fretting fatigue drawn on the literature, is presented to determine a quantitative measure to be used in assessing the surface wear resistance in conditions of contact cyclic loading. Operation practice and experiments indicate to multiple micro-cracks of different sizes present on the contact surface. An assumption is made regarding the accidental character of the crack birth thus making possible the use of the mathematical statistics to obtain the characteristics treated as the mechanical properties of the crack resistance, which assess the resistance of contact fatigue material. The samples of three steel grades used for railway rail production are studied. The wear resistance is assessed through robust statistical characteristics under the assumption that occurrence of the surface defects is a random process. The loading is carried out in conditions of rolling friction with the balls spinning in the mandrel, thus forming an annular wear pad. As the load on the test rig is considered an analogue of the force action of the wheel on the rail, the wear resistance can become a quantitative measure of the quality of the rail steel. Measurements on each sample were made for three runs. The curves of the density of the defect area distribution on the wear surface of the samples are presented. Quantitative characteristics are proposed to estimate the fretting fatigue resistance of the metal, namely, the average crack area, standard deviation and the variation coefficient. Those characteristics are the parameters of statistical processing of experimental observations of the number and size of the surface cracks that occur under cyclic loading of the metal surface. The degree of significance of the observed damages is discussed to be used as an indicator when comparing different steels in the wear resistance. The results of the experiment made it possible to arrange three studied steels in a series of their fretting corrosion resistance: the Japanese steel has the greatest resistance to contact wear, then Russian steel and then Polish steel that exhibits the least resistance to contact wear.

Experimental Study of the Effects of Surface Defects on Rolling Contact Fatigue Behavior

2007 ◽  
Vol 353-358 ◽  
pp. 254-257
Author(s):  
Guan Chen ◽  
Hong Ping Zhao ◽  
Shao Hua Ji ◽  
Xi Qiao Feng ◽  
Hui Ji Shi
Keyword(s):  
Failure Modes ◽  
Surface Defects ◽  
Fatigue Behavior ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Surface Cracks ◽  
Hardness Tester ◽  
Rolling Surface ◽  
Contact Fatigue Resistance

Rolling contact fatigue (RCF) cracks initiated from surface and subsurface defects are typical failure modes of bearing systems. In this paper, the effects of surface defects on RCF behavior of M50NiL and M50 steels were studied experimentally. Artificial dents were introduced on the rolling surface by using Rockwell hardness tester. The influences of dent shape and dent shoulders were examined by thrust-type RCF tests. Surface cracks initiation, propagation and spalling were monitored by scanning electron microscope (SEM) observation. The results showed that artificial dents reduce RCF lives of M50NiL and M50 steels with mineral oil lubrication. The fatigue failure initiates at the surface defect with the effects of dent shape and dent shoulder. M50NiL steel has higher contact fatigue resistance than M50. The features of surface and sub-surface cracks propagation during RCF tests were also observed.

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