Fatigue life evaluation of high-speed maglev train bogie under higher operating speed grade

Safety is the eternal research theme of rail transit, while higher-speed rail transit is the relentless pursuit goal.Compared with traditional wheel-rail trains, high-speed maglev trains are a new type of rail vehicle with higher speed possibilities.In order to guarantee the safety and structural reliability of the maglev train under higher operating speed grade, it is necessary to deeply study the fatigue life of key components of high-speed maglev trains during the research and development design phase.This paper takes a high-speed maglev train bogie as an example, presents a study of the dynamic simulation load of maglev bogie under the speed grade condition of 600 kilometers per hour and its effect on the fatigue damage of maglev bogie structure. Firstly, a multi-rigid car-rail coupling dynamics model of high-speed maglev train was established and the vehicle-rail coupled vibration and random track irregularity are considered as excitation. The vibration response of high-speed maglev train passing a curve line was analyzed at highspeed(400km/h) and higher-speed(600km/h). Dynamic simulation loads at critical load bearing positions of maglev bogie were obtained and compared. Next, a detailed finite element model of maglev bogie was established, dynamic stress-time histories of maglev bogie under dynamic simulation loads were obtained using a quasi-static stacking method. The rain flow counting method, Wohler curves and the Palmgren-Miner damage accumulation rule were applied to evaluate the fatigue life of the critical positions of maglev bogie. Finally, the distribution of maglev bogie fatigue hot spot positions and the effect of higher operating speed grade is discussed. The results show that vibration responses, dynamic simulation loads and fatigue damage of maglev bogie have increased significantly at higher operating speed grade. The fatigue life evaluation method based on dynamic simulation loads is an effective method to study the fatigue reliability of key components of high-speed maglev train. In order to improve the operational safety and structural reliability of maglev trains under higher operating speed grade, it is recommended to analyze the fatigue life of key components of high-speed maglev train in the research and development design phase. Fatigue life and maintenance cycle of maglev bogie can be improved, if analysis results of this paper are used to improve the structural design of fatigue hot spot positions.