Two Contributions to Rolling Contact Fatigue Testing Considering Different Diameters of Rail and Wheel Discs

Abstract

Scaled rolling contact fatigue tests, used to practically simulate the wear of the wheel and rail material under laboratory conditions, are typically classified into two categories. Tests in the first category use twin-disc stands, while the second group of test rigs use two discs of different diameters considering the rail disc as the larger one. The latter setup is closer to the real situation, but problems can occur with high contact pressures and tractions. The focus of this paper is on two main contributions. Firstly, a case study based on finite element analysis is presented, allowing the optimization of the specimen geometry for high contact pressures. Accumulated plastic deformation caused by cycling is responsible for abrupt lateral deformation, which requires the use of an appropriate cyclic plasticity model in the finite element analysis. In the second part of the study, two laser profilers are used to measure the dimensions of the specimen in real time during the rolling contact fatigue test. The proposed technique allows the changes in the specimen dimensions to be characterized during the test itself, and therefore does not require the test to be interrupted. By using real-time values of the specimen’s dimensional contours, it is possible to calculate an instantaneous value of the slip ratio or the contact path width.

Examining Wear Mechanisms in Railway Wheel Steels: Experimental Insights and Predictive Mapping

“…Over time, there has been extensive research conducted on wheel-rail wear. Several researchers have conducted laboratory tests (small-scale) [2][3][4][5][6][7][8][9][10][11] and field experiments [12][13][14][15][16][17][18][19]. The former are usually preferred because of their cost-effectiveness and more accurate investigation of the material responses at the expense of the dynamic responses (lateral forces).…”

“…For example, Bolton and Clayton [70] proposed an approach based on the dissipated energy responsible for wear, defined as Tγ/A, where T, γ, and A are the traction force, creepage, and contact area, respectively. This parameter was plotted against the wear rate, calculated as the mass loss in µg divided by rolling distance in meters and the contact area in mm 2 . This approach identified three wear regimes: mild, severe, and catastrophic [70][71][72][73][74][75][76].…”