Study on End Underframe Fatigue Life of a Certain Type of Metro Train

Abstract

Objective The car body of metro vehicle is a welded structure, and its fatigue strength is obviously smaller than that of the base metal due to the influence of stress concentration, welding defects and welding residual stress. As the part connecting bogie and car body, the end underframe of metro vehicle bears more load.Therefore, it is necessary to study its fatigue life. Method The numerical simulation and fatigue test are jointly used to study the fatigue life of the end underframe of a certain type of metro train. Firstly, a finite element model of metro vehicle is established and the corresponding fatigue load and evaluation points are determined.Then, the fatigue damage simulation is carried out on the whole train and the end underframe respectively. Finally,the bench test on the end underframe is performed, and the result is compared with that of the train fatigue test and the simulation result of the end underframe. Result & Conclusion Under the condition of unidirectional fatigue damage and combined load fatigue damage, both the vehicle chassis (underframe) and the end underframe of the metro train car body have no risk of cracking, meeting the requirements of the relevant standards. Meanwhile, the end underframe can obtain more conservative results in fatigue test when the load is amplified, and the simulation results of the end underframe finite element model are in good agreement with its test results, which can truly reflect the stress state of the train model and meet the requirements of the relevant standards.

Keywords

• metro train
• end underframe
• fatigue test
• finite element