RAIL ANALYSIS. VOLUME 1: FRACTURE MECHANICS. FRACTURE MECHANICS OF RAILS WITH SHELL-INITIATED TRANSVERSE DEFECTS

This report describes a fracture mechanics model for rail head transverse defects, specifically detail fractures from rail shell. The model is applied to calculate the failure strength of 71 rail segments which were rejected by inspection, removed, and tested through three-point bending by the Association of American Railroads. Utilizing the defect measurements for each rail, reasonable agreement is obtained between observed failure loads and failure loads calculated from the stress and fracture mechanics analysis. The fracture mechanics analysis is then extended to obtain preliminary estimates of the fatigue performance of defective rails in service. Specifically, the crack tip stress intensity factor is calculated for transverse defects under various types of in-service loading. The fracture mechanics solutions are utilized to conservatively calculate the remaining lifetime of the rail as a function of defect size and magnitude of wheel load. Calculations indicate that the shear stress reversal experienced as the wheel crosses a transverse crack is the dominant stress component causing fatigue crack propagation. Recommendations are made for additional analytical developments and experimental results required to refine the fatigue life predictions and incorporate them into programs for risk assessment and reliability optimization.

• Supplemental Notes:
  • This document is the first in a series describing research in Phase 2 of the Train Track Dynamics Program, a cooperative program of the AAR, FRA, RPI and Canadian Transportation Development Agency.
• Corporate Authors:

  Failure Analysis Associates

  750 Welch Road
  Palo Alto, CA  United States  94304
• Authors:
  • Besuner, P S
• Publication Date: 1976-10

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 135 p.

Subject/Index Terms

• TRT Terms: Axle load force; Defects; Dynamics; Failure; Failure analysis; Fracture mechanics; Mathematical models; Rail (Railroads); Service life; Train track dynamics; Wheel loads; Wheels
• Old TRIS Terms: Axle loadings; Rail failure
• Subject Areas: Design; Railroads; Vehicles and Equipment;

Filing Info

• Accession Number: 00147715
• Record Type: Publication
• Source Agency: Association of American Railroads
• Report/Paper Numbers: R-225 Tech. Rpt.
• Contract Numbers: FAA-75-1-1(B)
• Files: TRIS
• Created Date: Feb 16 1977 12:00AM