| It is important to ensure the operation safety of the metro vehicle, which acts as one of the main modes of transportation within the city. In view of the metro vehicle’s running status, its operation condition is bad due to the frequent starting and braking, coupling with the complexity and variability of rail lines. The fatigue failure of the bogie frame often occurs, which is the key component of metro vehicle. So, it is very important to predict the fatigue life of the bogie frame, which has an great influence on the safety operation of the metro vehicle.The main reason which caused the structure to failure is the perturbation of amplitude stress. Taking a certain type of metro vehicle as an example, during its operation process, it has found that part areas of the bogie frame have crack phenomenon, which has an influence on the safety operation of the vehicle. So, find the reasons that caused the crack of structure, and make an optimization design on the local structure of the frame, thereby improving the fatigue life to meet the design requirements of the bogie frame. In this paper, taking the rigid-flexible coupling multibody dynamics simulation of metro vehicle, finite element analysis of structure, fatigue analysis of structure, fatigue life prediction of structure, optimization of structure as the methods to make a system research on this type bogie frame of metro vehicle. The related research work is as follows:(1) Analysis the structure characteristics and stress mode of the frame. Establishing the finite element model of the frame, and get the natural vibration characteristics and inherent frequency through modal analysis;(2) Establish the flexible frame by UM-ANSYS co-simulation based on fixed interface modal synthesis method, combined with the modeling method for rail vehicle multibody dynamics, and establish the rigid-flexible coupling multibody dynamics model of metro vehicle with the help of UM-RAIL. Analysis and compare the vibration response between flexible frame and rigid frame, thus highlights the necessity to consider the frame as flexible body;(3) Make a systematic research on the calculation method of structure dynamic stress, adopt a new method based on flexible body to calculate the dynamic stress. Combine with the actual operation condition of the vehicle, and formulate a reasonable dynamics simulation conditions of metro vehicle. The dynamic stress response of frame is carried out based on rigid-flexible coupling multibody dynamic model of the metro vehicle, from which vibration characteristics of this type of the frame can be obtained, then, failure mechanism of the frame can be obtained based on fatigue analysis of local fatigue areas of the frame;(4) Predict fatigue life for local fatigue area of the frame-the structure of motor suspension by using the quasi-static stress superposition method. The simulation results have accord with the actual situation. Optimize the size of motor suspension based on the fatigue life constraints of the structure. Reconstruct the rigid-flexible coupling multibody dynamics model of the metro vehicle based on the optimized structure. Compare and analysis performance index such as the static strength results, fatigue life, dynamic stress response before and after, thus verify the rationality of the optimized structure. At last, form a new optimization method which consider the external dynamic load and the material properties that has an influence on the fatigue life of the structure.The article make a system research on the dynamics analysis, fatigue analysis, structure’s life prediction, and structure optimization of the frame based on CAE simulation method. The vibration characteristics of structure, the failure mechanism of structure, the fatigue life of structure can be obtained in the early stages by means of this method. Thus avoid the occurrence of fatigue failure phenomenon in the using process of the frame, which is helpful to improve the operation safety of metro vehicles. |
PDF Full Text Request