Abstract
The fatigue strength of weld surfaces on truck frames has been estimated according to the fatigue limit diagram in JIS E 4207, General Rules for Design of Truck Frames for Railway Rolling Stock. However, it is not possible to predict actual fatigue life using this diagram. This study demonstrates the possibility of fatigue life estimation for welds on truck frames based on a modified Miner's rule. In order to estimate fatigue life, three factors are needed: the S-N diagram assumed from the allowable stress in JIS E 4207 or the JSSC fatigue design curve, the relationship between crack occurrence and running distance, and the stress frequency distribution caused by service loads.
