Visualization and Modelling to Understand Rail Rolling Contact Fatigue Cracks in Three Dimensions

This article presents an extensive survey of experimental data on rolling contact fatigue (RCF) crack shape and propagation characteristics in rails removed from service, where such cracks are angled to the rail axis. The data includes re-analysis of previously published experimental data to extract crack shape information and new experimental work on crack shapes at different stages in the early RCF life. Periods from initiation (ratcheted ‘flake cracks’) have been considered through very early growth to the limit of 1 prior austenite (PA) grain and on to rail-head visual cracks. Techniques included multi-sectioning through single cracks and crack zones, on used rail and test discs, to build up real 3-D data on crack shapes and propagation characteristics. This data has been compared with the United Kingdom rail system guidance charts relating to visual crack length and respective vertical depth; all data fell within the indicated guidance zones. The configuration of such angled cracks, typically found in curves, so aligned due to the vector of both lateral and longitudinal traction, rather than just axially, was identified as an important case for modeling. A fracture mechanics-based model was developed to predict modes I and II stress intensity factors for such cracks covering multiple PA grains. An important geometry effect is revealed by which a contact approaching a crack angled to the rail axis is effectively ‘offset’ from the approach direction considered in 2-D models, thereby resulting in lower predicted peak stress intensity factor values, compared with 2-D, for prediction of crack growth rates.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/09544097
• Authors:
  • Garnham, J E
  • Fletcher, D I
  • Davis, C L
  • Franklin, F J
• Publication Date: 2011-3

Language

• English

Media Info

• Media Type: Print
• Features: Figures; Photos; References; Tables;
• Pagination: pp 165-178
• Serial:
  • Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
  • Volume: 225
  • Issue Number: 2
  • Publisher: Sage Publications Limited
  • ISSN: 0954-4097
  • EISSN: 2041-3017
  • Serial URL: http://pif.sagepub.com/content/current

Subject/Index Terms

• TRT Terms: Fatigue cracking; Railroad engineering; Railroad rails; Rolling contact
• Subject Areas: Railroads; Terminals and Facilities;

Filing Info

• Accession Number: 01339925
• Record Type: Publication
• Files: TRIS
• Created Date: May 18 2011 10:51AM