2005 Volume 46 Issue 4 Pages 250-255
Jointed rails are replaced periodically in Japan. Their service life is governed mainly by the fracture at the joints. To evaluate the fatigue life of jointed rails, it is necessary to verify the stress distribution around fish-bolt holes and an S-N curve of jointed rails. Therefore, we carried out static loading tests in a laboratory and field tests to measure the stresses around the fish-bolt holes, and further dynamic stress analysis of jointed rails and bending fatigue tests of rails used in the field.
The dynamic stress analysis model is composed of a beam model to calculate dynamic wheel/rail contact forces and a solid model to calculate stress distribution resulting from those contact forces. These models were validated using field test data. Based on the study results, we established a method to evaluate the fatigue life of jointed rails. In this method, we calculated the stresses under several combined conditions of jointed rail, vehicle type and vehicle speeds.
The fatigue life was calculated by applying the stresses to the S-N curve. As a result, the rail replacement period have a potential to be extended except in cases of heavy wear between a fishplate and rail.