LIFE-TIME MANAGEMENT OF RAILS BASED ON STRUCTURAL RELIABILITY APPROACH

Abstract

Preventing derailment due to broken rails is an area
of high priority for keeping a safe rail industry. The
common method to control the risk of rail breaking
is a frequent rail inspection through nondestructive
testing technologies and a replacement of rails
based on the remedial action plans. However, determining
the effective (optimal) inspection frequency
is not an easy task and setting exact inspection intervals
requires critical decisions in railway infrastructure
management.
In this research paper, the rail model is developed
using ABAQUS/CAE and FRANC3D software and
fracture mechanics is used for the determination of
critical crack -size at a rail head, web and base as
well as fatigue life of rail. First order reliability
analysis is carried out and reliability of rail as well
as a mechanism of remedial action is recommended
to help an infrastructure manager’s decision. Eventtree
analysis and life cycle cost estimation is also
conducted.
Based on the analysis results, an annual, uniform
and effective rail inspection frequency is assessed
with 99.5% rail reliability for the applied stress and
tonnage using non-destructive technologies which
result in minimal total cost. Finally, critical cracks
of rail before failure are determined as1mm for rail
head, 5 mm for the rail web and 2 mm for the rail
base to help infrastructure managers’ (track engineers
or rail inspectors) decision for replacement