“…This is a very complex topic where much research is still required, cf. 16–18 Figure 4.Rail with about a week of heavy haul traffic after grinding. Remaining gauge corner cracks indicated by inclined marks partially worn off by a passing train.…”
Section: Rail Machining Objectives and Consequences Of Not Achieving ...mentioning
confidence: 99%
“…This is a very complex topic where much research is still required, cf. [16][17][18] To further understand the influence of remaining cracks after grinding, note that RCF cracks tend to initially propagate in a shallow angle to the surface, which deviates to a steeper angle that may be interrupted by a transition or branching to growth perpendicular and/or parallel to the surface, see Figure 5. When the upper part of the crack is ground off, remaining cracks will have an orientation different from the 'preferred' growth direction.…”
Current practices on rail machining show large variations in strategies and amount of grinding and milling. To identify reasons for this and suggest strategies to further optimise rail machining, objectives of machining are scrutinised and consequences of not fulfilling objectives are investigated. This leads to a discussion on potentially detrimental effects of rail machining and how to minimise these. With this background, general aspects of rail machining optimisation are discussed. The study shows several means to improve rail machining, but also how the potential is restricted by the current lack of knowledge and predictive models. This prevents quantifying benefits of innovative solutions, and complicates transfer of knowledge between different operational conditions and translations of (scaled and controlled) test results to (full-scale, uncontrolled) operational conditions.
“…This is a very complex topic where much research is still required, cf. 16–18 Figure 4.Rail with about a week of heavy haul traffic after grinding. Remaining gauge corner cracks indicated by inclined marks partially worn off by a passing train.…”
Section: Rail Machining Objectives and Consequences Of Not Achieving ...mentioning
confidence: 99%
“…This is a very complex topic where much research is still required, cf. [16][17][18] To further understand the influence of remaining cracks after grinding, note that RCF cracks tend to initially propagate in a shallow angle to the surface, which deviates to a steeper angle that may be interrupted by a transition or branching to growth perpendicular and/or parallel to the surface, see Figure 5. When the upper part of the crack is ground off, remaining cracks will have an orientation different from the 'preferred' growth direction.…”
Current practices on rail machining show large variations in strategies and amount of grinding and milling. To identify reasons for this and suggest strategies to further optimise rail machining, objectives of machining are scrutinised and consequences of not fulfilling objectives are investigated. This leads to a discussion on potentially detrimental effects of rail machining and how to minimise these. With this background, general aspects of rail machining optimisation are discussed. The study shows several means to improve rail machining, but also how the potential is restricted by the current lack of knowledge and predictive models. This prevents quantifying benefits of innovative solutions, and complicates transfer of knowledge between different operational conditions and translations of (scaled and controlled) test results to (full-scale, uncontrolled) operational conditions.
“…Following the first works of Way [1], rolling contact fatigue (RCF) has been the subject of numerous studies [2][3][4][5]. However, the damage process, and especially crack growth are not fully understood.…”
Section: Introductionmentioning
confidence: 99%
“…In mode II, the effects of various extrinsic phenomena (crack face contact and friction, oxidation, plastic deformation of asperities, wear and debris formation) make the analysis of the crack growth kinetics and path complex [5,23]. These interactions decrease the effective range of the stress intensity factor in mode II (ΔK , ), even without any normal compression, because of asperities along the crack faces, which oppose the sliding displacements [23,33].…”
Section: Introductionmentioning
confidence: 99%
“…5, which resulted in their arrest. Meanwhile, crack #4 grew in mode I over 0.95 mm, while crack #1 coplanar to the notch continued to grow in mode II, without bifurcation, over 2.3 mm, and crack #2 stopped growing, because of the shielding effect from crack #3 and crack #4.…”
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