Fatigue Analysis for Bogie Frame of Urban Transit Rail Vehicle under Overload Situation

With the rapid development of the urban transit rail, overload operation has become one of the main reasons for the failure of urban transit rail vehicle structure. Herein, we conducted a tracking experiment on the urban transit rail vehicle in-service and investigated the fatigue life of the bogie frame. Load experiment of urban transit rail vehicle was carried out to measure the maximum vertical load and obtain the load histories under overload situation. Furthermore, based on JIS E4207 standard, the stress of ten main in-service cases is calculated using finite element method. According to the actual operation results, five critical stress locations are chosen to assess the fatigue strength of bogie frame. A new fatigue limit diagram combined with Morrow relation is applied to analyze fatigue strength of these locations and is utilized to identify if the positions are dangerous. The investigation result shows the welding location around air spring seat cannot satisfied the necessary of fatigue lifetime.