Cyclic Crack Growth under Repeated Rolling Contact

1985 ◽  
pp. 271-280 ◽  
Author(s):  
H. Yoshimura ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Crack Growth ◽  
Rolling Contact

Estimation of Crack Growth Life in Rail with a Squat Defect

2009 ◽  
Vol 417-418 ◽  
pp. 313-316 ◽  
Author(s):  
Hyun Kyu Jun ◽  
Won Hee You
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Rail Steel ◽  
Crack Tip ◽  
Cost Effective ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Maintenance Strategy ◽  
Whole Life Cycle

Rolling contact fatigue initiated defects such as surface corrugation, head check, squat, are one of growing problems in high speed railway line. A squat is generally developed below the rail surface and grows parallel to surface until it turns down into rail. Estimation of critical crack size and crack growth rate is an essential to prevent rail from failure and develop cost effective railway maintenance strategy. In this study, we predict crack growth rate of a rail with a squat defect. For this purpose, a rail model with a squat defect is developed. Timoshenko’s beam theory is applied to calculate the global bending stress at the crack tip and Hertzian contact model is applied to calculate the local contact stresses at the surface of rail by simulating rolling over a railway wheel on a rail. Stress intensity factors are calculated from the total stress at the crack tip. Fatigue crack growth curve of 60kg rail steel is applied to calculated crack growth rate. Software to predict crack growth life through whole life cycle is developed. We expect that we can make a more cost effective rail maintenance strategy by considering the crack growth analysis for a defective rail.

A technique for studying crack growth under repeated rolling contact

Wear ◽  
1984 ◽  
Vol 95 (1) ◽  
pp. 29-34 ◽  
Author(s):  
H. Yoshimura ◽  
C.A. Rubin ◽  
G.T. Hahn
Keyword(s):  
Crack Growth ◽  
Rolling Contact

The Effects of Indent Residual Stresses on Mixed Mode Cyclic Crack Growth Driving Forces for Bearing Inner Rings

1987 ◽  
Vol 109 (4) ◽  
pp. 634-639 ◽  
Author(s):  
V. Bhargava ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Crack Growth ◽  
Driving Forces ◽  
Rolling Contact ◽  
Crack Face ◽  
Press Fit ◽  
Compressive Stresses ◽  
Peak Contact Pressure ◽  
Peak Pressures

The residual stresses produced by plastic dents in a solid cylinder have been evaluated for overload, peak-contact-pressure-to-shear-strength ratios of poi/k = 3.5, and poi/k = 4. The effects of 2 sets of indent residual stresses on the cyclic crack growth driving forces generated by rolling contact at relative peak pressures of por/k = 0.5, 1.0 and 2.0, have been evaluated for 3 conditions. These are: (1) the slowly revolving ring, (2) the rapidly revolving ring with associated press fit and centrifugal stresses, and (3) the rapidly revolving ring with the superimposed circumferential compressive stresses arising from a carburized surface layer. The values of ΔKI ΔKII, and the combined mode, ΔKe, are calculated for 18 different rolling conditions, for small cracks with 8 different inclinations, 5 crack-face friction coefficients, and 21 locations in the dent region. The results show that the ΔK-values for a 2a=20μm long crack can exceed the Mode I threshold when the rim rotates slowly. Larger ΔK-values are obtained in the presence of press-fit and centrifugal stresses. However, the residual stresses of the carburized surface layer more than compensate for the press-fit and centrifugal stresses, reducing the ΔK-values below the levels obtained for the slowly rotating rim.

Dry and lubricated wear of rail steel under rolling contact fatigue - Wear mechanisms and crack growth

Wear ◽  
2017 ◽  
Vol 380-381 ◽  
pp. 240-250 ◽  
Author(s):  
Santiago Maya-Johnson ◽  
Juan Felipe Santa ◽  
Alejandro Toro
Keyword(s):  
Crack Growth ◽  
Wear Mechanisms ◽  
Rail Steel ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Fatigue Wear

Relationships between the fatigue crack growth resistance characteristics of a steel and the tread surface damage of railway wheel

2018 ◽  
Vol 2 (90) ◽  
pp. 49-55 ◽  
Author(s):  
O.P. Ostash ◽  
V.V. Kulyk ◽  
T.M. Lenkovskiy ◽  
Z.A. Duriagina ◽  
V.V. Vira ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Crack Growth Resistance ◽  
Rolling Contact ◽  
Wheel Steel ◽  
Fatigue Crack Growth Resistance ◽  
Railway Wheels

Purpose: The aim of the proposed research is to establish experimentally the relation between damaging of the tread surface of model wheels and the characteristics of fatigue crack growth resistance of wheel steels "KI th, "KII th, "KI fc, "KII fc), depending on its microstructure. Design/methodology/approach: Characteristics of the fatigue crack growth resistance have been determined on the specimens cut out from the hot rolled plate of thickness 10 mm of the steel which is an analogue of railway wheel steels. To obtain different steel microstructures and its strength level, test specimens were quenched (820°C, in oil) and then tempered at 400°C, 500°C, and 600°C for 2 h. The characteristics of Mode I fatigue crack growth resistance of steel were determined on the basis of fatigue macrocrack growth rate diagrams da/dN–"KI, obtained by the standard method on compact specimens with the thickness of 10 mm at a frequency of 10-15 Hz and the stress ratio R = 0.1 of the loading cycle. The characteristics of Mode II fatigue crack growth resistance were determined on the basis of da/dN–"KII diagrams, obtained by authors method on edge notched specimens with the thickness 3.2 mm at a frequency of 10-15 Hz and R = –1 taking account of the crack face friction. The hardness was measured with a TK-2 hardness meter. Zeiss-EVO40XVP scanning electron microscope was used for microstructural investigations. Rolling contact fatigue testing was carried out on the model specimens of a wheel of thickness 8 mm and diameter 40 mm in contact with a rail of length 220 mm, width 8 mm and height 16 mm. Wheels were manufactured form the above-described steel after different treatment modes. Rails were cut out from a head the full-scale rail of hardness 46 HRC. The damaging was assessed by a ratio of the area with gaps formed by pitting and spalling to the general area of the wheel tread surface using a special stand. Findings: The growth of the damage of the tread surface of the model wheels correlates uniquely with the decrease of the cyclic fracture toughness of the wheel steel "KI fc and "KII fc, determined at Mode I and Mode II fracture mechanisms. These characteristics of the wheel steel can be considered as the determining parameter of this process, in contrast to the fatigue thresholds "KI th and "KII th. Research limitations/implications: Investigations were conducted on model wheels that simulate the damage of real railway wheels tread surface. Practical implications: A relationship between the damage of tread surface of railway wheels and the strength level of wheel steels is determined. Originality/value: The damage of the tread surface of the model wheels during the rolling contact fatigue of the pair wheel-rail increases with the growth of the strength (hardness) of the wheel steel, which corresponds to the statistical data of the operation of the real railway wheels.

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