New Fatigue Life and Durability Evaluating Method of High Speed Train Carbody Structure

摘要

With the development of new generations of CRH trains in China,one new fatigue integrated analysis method was proposed to evaluate high speed train carbody structure fatigue life and durability.The CRH train's carbody structure was used here as an example for study the interaction relation between vehicle dynamic characteristic and fatigue property running in BEIJING-TIANJIN intercity line.The detail method steps include: Firstly,MBS (Multi Body Simulation) technologies allowed the development of more detailed and accurate vehicle-rail rigid-flexible coupled dynamics model which can be used as input of stress distribution calculation.And The typical carbody structure's fatigue load spectrum and extrapolation were calculated here through quasi-static stress method according to field running condition for different radius curve (400-2500 m),which was random combination of Track irregularity,W/R profile and Cant deficiency.Secondly,Aluminum alloy structure FE (Finite Element) analysis technologies,such as modal analysis,substructure and stress calculation,were used to determine structure critical location and understand carbody structure nature frequencies and mode shapes influence.FM (Fracture Mechanics) assessment analysis for different load condition combination based on the structure stress distribution and stress/strain time histories results.Thirdly,carbody structure fatigue stress distributions in carbody selected dangerous regions were calculated in sub-model.And The analysis results were compared with the field dynamic stress test results.Finally,carbody fatigue life and durability analysis results were estimated based on aluminum material S-N curve with Palmgren-Miner damage cumulative theory.The critical structure fatigue failure influence can be taken into account in stress distribution used as input of FM.This work targets the capabilities of MBS and FEM (Finite Element Method) in the fatigue and durability design early stage and verification phase of the high speed train key structure,such as bogie structure,axle and wheel,etc.The results also illustrate that the proposed numerical simulation method can give an important contribution in terms of high speed train key structure component fatigue and durability evaluation.