Estimation of Fatigue Life and Failure Probability of Welded Joints in the Railway Bogie Frame Utilizing the Partial Safety Factor Method (JIS B9955-2017)

Abstract

The present study aimed at clarifying the relationship between fatigue life under in-service conditions and failure probability on welded joints in railway bogie frame. Considering effects of stress ratio and weld toe radius, the authors determined P-S-N curves using fatigue data of cruciform as-welded joints. An estimation method of the probability of fatigue failure was proposed based on the partial safety factor method (JIS B9955-2017，JSME S 018-2018). The proposed method enabled considering the deviation of the in-service cyclic stress. The method was applied to a vehicle with a modified Miner’s rule and above P-S-N curves. It was clarified that the failure probability increased with an increase in the mileage of the vehicle, and the relationship between the failure probability and the mileage varies because of the deviation of in-service stress.