Strength Analysis And Fatigue Life Prediction Of Metro Body Bolster Under The Combined Load Cases

While economies of individual countries continue to flourish,traffic problems have become more serious,metro compared with other public transport,has certain advantages in maneuverability,speed,passenger capacity and manufacturing costs and become an important means to solve urban traffic problems.Body bolsters,as traction and transmission bridges between metro body and bogie,are key parts of the metro chassis and subjected to tensile and pressure loads.Body bolsters have large size,relatively complex geometry and theses stress distribution are more complex than other parts,so as to have important impacts on the safety and reliability of vehicle operation,so it is important to predict body bolsters life.In this paper,the starting is finite element theory,then static strength analysis of metro vehicle under combined load cases have been completed and the load spectrum has been established based on the results,finally,theories of multiaxial fatigue life have been used to predict body bolsters life.The main work is as follows:First of all,according to the standard JIS-7105 and JIS-7106 under the single fatigue load cases,combined with the actual situation of the process of metro operation to determine the metro vehicle suffered 16 kinds load conditions.Secondly,use Hyperworks to complete vehicle body strength analysis,and the strength analysis results have been extracted to determine 8 fatigue danger points at the body bolster.Thirdly,according to changes of metro load cases on the specific line,the mathematical model of the vehicle load spectrum has been established,and the model having been programmed by Matlab to formulate the load spectrum of fatigue dangerous points at the body bolster of Guangzhou metro line 5.Finally,body bolsters life have been estimated by equivalent stress and critical plane methods based on multiaxial fatigue theories,combined with load compression theory,rainflow counting method,S-N curve,Goodman mean stress correction criterion and Miner linear cumulative damage theory.In this paper,the fatigue life prediction of the body bolster is universal and the same applies to body bolsters of other lines.