Rolling contact fatigue
Rolling Contact Fatigue (RCF) is a phenomenon that occurs in mechanical components relating to rolling/sliding contact, such as railways, gears, and bearings.[2] It is the result of the process of fatigue due to rolling/sliding contact.[2][3] The RCF process begins with cyclic loading of the material, which results in fatigue damage that can be observed in crack-like flaws, like white etching cracks.[2] These flaws can grow into larger cracks under further loading, potentially leading to fractures.[2][4]
In railways, for example, when the train wheel rolls on the rail, creating a small contact patch that leads to very high contact pressure between the rail and wheel.[2] Over time, the repeated passing of wheels with high contact pressures can cause the formation of crack-like flaws that becomes small cracks.[2] These cracks can grow and sometimes join, leading to either surface spalling or rail break, which can cause serious accidents, including derailments.[2][4]
RCF is a major concern for railways worldwide and can take various forms depending on the location of the crack and its appearance.[2] It is also a significant cause of failure in components subjected to rolling or rolling/sliding contacts, such as rolling-contact bearings, gears, and cam/tappet arrangements.[5] The alternating stress field in RCF can lead to material removal, varying from micro- and macro-pitting in conventional bearing steels to delamination in hybrid ceramics and overlay coatings.[5]
Basics
Testing
Testing for RCF involves several methods, each designed to simulate the conditions that cause RCF in a controlled environment. Here are some of the methods used:
- Twin-Disc Stands: This method uses two discs to simulate the wear the occur for rails and wheels.
- Scaled RCF Tests: These tests use two discs of different diameters.[6]
- Three-Ball-on-Rod Tester: This is an economical RCF proof of concept test. It is performed to evaluate the influence of heat treatment, material, lubricant, and coatings on fatigue life.[6]
- Lundberg-Palmgren Theory and ISO 281 Based Method: This method evaluates RCF reliability considering the contact load, the geometric parameters of contact pairs, the oscillation amplitude, the RCF reliability, and the material properties.[7]
Triple disc rolling contact fatigue (RCF) Rig is a specialised testing apparatus used in the field of tribology and materials science to evaluate the fatigue resistance and durability of materials subjected to rolling contact.[8] This rig is designed for simulating the conditions encountered in various mechanical systems, such as rolling bearings, gears, and other components exposed to repeated rolling and sliding motions. The rig typically consists of three discs or rollers arranged in a specific configuration.[9] These discs can represent the interacting components of interest, such as a rolling bearing. The rig also allows precise control over the loading conditions, including the magnitude of the load, contact pressure, and contact geometry.[10][11]
PCS Instruments Micro-pitting Rig (MPR) is a specialised testing instrument used in the field of tribology and mechanical engineering to study micro-pitting, a type of surface damage that occurs in lubricated rolling and sliding contact systems. The MPR is designed to simulate real-world operating conditions by subjecting test specimens, often gears or rolling bearings, to controlled rolling and sliding contact under lubricated conditions.[12]See also
- Contact mechanics – Study of the deformation of solids that touch each other
- Derailment
- Fretting – Wear or damage on loaded surfaces
- Frictional contact mechanics
- Friction – Force resisting sliding motion
- Wear – Damaging, gradual removal or deformation of material at solid surfaces
- Rolling-element bearing
- Tribology
- Rolling (metalworking)
- Surface roughness – Measure of surface finish or texture
- Lists of rail accidents
References
- ^ Curd, M. E.; Burnett, T. L.; Fellowes, J.; Donoghue, J.; Yan, P.; Withers, P. J. (2019-08-01). "The heterogenous distribution of white etching matter (WEM) around subsurface cracks in bearing steels". Acta Materialia. 174: 300–309. Bibcode:2019AcMat.174..300C. doi:10.1016/j.actamat.2019.05.052. ISSN 1359-6454.
- ^ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Kapoor, Ajay; Salehi, Iman; Asih, Anna Maria Sri (2013), "Rolling Contact Fatigue (RCF)", in Wang, Q. Jane; Chung, Yip-Wah (eds.), Encyclopedia of Tribology, Boston, MA: Springer US, pp. 2904–2910, doi:10.1007/978-0-387-92897-5_287, ISBN 978-0-387-92897-5, retrieved 2024-03-14
- ^ "Rolling Contact Fatigue – About Tribology". Retrieved 2024-03-14.
- ^ 4.0 4.1 Kang, Young Sup (2013), "Rolling Bearing Contact Fatigue", in Wang, Q. Jane; Chung, Yip-Wah (eds.), Encyclopedia of Tribology, Boston, MA: Springer US, pp. 2820–2824, doi:10.1007/978-0-387-92897-5_375, ISBN 978-0-387-92897-5, retrieved 2024-03-14
- ^ 5.0 5.1 Ahmed, R. "Rolling Contact Fatigue" (PDF). Heriot-Watt University.
- ^ 6.0 6.1 Šmach, Jiří; Halama, Radim; Marek, Martin; Šofer, Michal; Kovář, Libor; Matušek, Petr (December 2023). "Two Contributions to Rolling Contact Fatigue Testing Considering Different Diameters of Rail and Wheel Discs". Lubricants. 11 (12): 504. doi:10.3390/lubricants11120504. ISSN 2075-4442.
- ^ Hai, Gao Xue; Diao, Huang Xiao; Jing, Hong Rong; Hua, Wang; Jie, Chen (2012). "A Rolling Contact Fatigue Reliability Evaluation Method and its Application to a Slewing Bearing". Journal of Tribology. 134. doi:10.1115/1.4005770. Retrieved 2024-03-14.
- ^ Ruellan, Arnaud; Cavoret, Jérôme; Ville, Fabrice; Kleber, Xavier; Liatard, Bernard (February 2017). "Understanding white etching cracks in rolling element bearings: State of art and multiple driver transposition on a twin-disc machine". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology. 231 (2): 203–220. doi:10.1177/1350650116648058. ISSN 1350-6501. S2CID 113573608.
- ^ Kunzelmann, Björn; Rycerz, Pawel; Xu, Yilun; Arakere, Nagaraj K.; Kadiric, Amir (2023-03-01). "Prediction of rolling contact fatigue crack propagation in bearing steels using experimental crack growth data and linear elastic fracture mechanics". International Journal of Fatigue. 168: 107449. doi:10.1016/j.ijfatigue.2022.107449. ISSN 0142-1123.
- ^ Richardson, A. D.; Evans, M.-H.; Wang, L.; Wood, R. J. K.; Ingram, M.; Meuth, B. (2017-11-27). "The Evolution of White Etching Cracks (WECs) in Rolling Contact Fatigue-Tested 100Cr6 Steel". Tribology Letters. 66 (1): 6. doi:10.1007/s11249-017-0946-1. ISSN 1573-2711. PMC 6951819. PMID 31983861.
- ^ Manieri, Francesco; Stadler, Kenred; Morales-Espejel, Guillermo E.; Kadiric, Amir (2019-03-01). "The origins of white etching cracks and their significance to rolling bearing failures". International Journal of Fatigue. 120: 107–133. doi:10.1016/j.ijfatigue.2018.10.023. ISSN 0142-1123. S2CID 139339152.
- ^ Gould, Benjamin; Greco, Aaron (2015-10-17). "The Influence of Sliding and Contact Severity on the Generation of White Etching Cracks". Tribology Letters. 60 (2): 29. doi:10.1007/s11249-015-0602-6. ISSN 1573-2711. S2CID 138178455.