Engineering: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]
See also
- Physics:Contact mechanics – Study of the deformation of solids that touch each other
- Physics:Fretting – Wear or damage on loaded surfaces
- Physics:Frictional contact mechanics – Study of the deformation of bodies in the presence of frictional effects
- Physics:Friction
- Physics:Wear – Damaging, gradual removal or deformation of material at solid surfaces
- Physics:Rolling-element bearing – Bearing which carries a load with rolling elements placed between two grooved rings
- Physics:Tribology
- Engineering:Rolling (metalworking) – Metal forming process
- Physics:Surface roughness – Measure of surface finish or texture
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. doi:10.1016/j.actamat.2019.05.052. ISSN 1359-6454. Bibcode: 2019AcMat.174..300C.
- ↑ 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), Wang, Q. Jane; Chung, Yip-Wah, eds. (in en), Rolling Contact Fatigue (RCF), Boston, MA: Springer US, pp. 2904–2910, doi:10.1007/978-0-387-92897-5_287, ISBN 978-0-387-92897-5, https://doi.org/10.1007/978-0-387-92897-5_287, retrieved 2024-03-14
- ↑ "Rolling Contact Fatigue – About Tribology" (in en-US). https://www.tribonet.org/wiki/rolling-contact-fatigue/.
- ↑ 4.0 4.1 Kang, Young Sup (2013), Wang, Q. Jane; Chung, Yip-Wah, eds. (in en), Rolling Bearing Contact Fatigue, Boston, MA: Springer US, pp. 2820–2824, doi:10.1007/978-0-387-92897-5_375, ISBN 978-0-387-92897-5, https://doi.org/10.1007/978-0-387-92897-5_375, retrieved 2024-03-14
- ↑ 5.0 5.1 Ahmed, R.. "Rolling Contact Fatigue". https://home.eps.hw.ac.uk/~mcera/Publications/Books/ASM-Handbook.pdf.
- ↑ 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" (in en). 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. https://doi.org/10.1115/1.4005770. Retrieved 2024-03-14.
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