Reliability Research And Dynamic Stress Characteristics Analysis For CRH380A Bogie Frame

The frame is the key component of the high speed train bogie. With the speed improved, stricter requirements for the boige frame’s fatigue strength were put forward.The stress spectrum of the bogie frame and its distribution are important for the fatigue evaluation and reliability design of the bogie.Therefore,the CRH380A bogie frame was taken as a research object in this paper.In combination of simulation calculation and railway-line test the frame’s dynamic stress characterestics were studied and its fatigue strength was evaluated The test is based on the CRH380A high speed EMU tracking trial of the Laboratory for Structure Strength Testing,Beijing Jiaotong University.The mainly contents of this thesis are as followed:Firstly,create the model of the bogie frame which was then analyzed in the simulation working conditions in Ansys.The calculation results show that the bogie frame meet the fatigue strength standards.The frame’s modal was also analyzed.the first six vibration modes and the corresponding natural frequencies were acquired.The first one is44.2Hz and its mode is reverse nod to both sides of the beam.Secondly,based on gained stress-time data of the key areas of the bogie frame,the effect of different ladders of stress spectrum on its accuracy and the damage calculation was studied.According to the results the sixteen-ladder spectrum was choosen to be used.Thirdly,The stress spectrums were made and the distribution of the spectrums was analyzed,which shows the stress conforms to Weibull distribution and truncated normal distribution.The maxium stress was deduced according to Weibull distribution.Fourthly,calculate the damage of bogie frame respectively according to Miner’s linear cumulative damage theory and Corten-Dolan’s nonlinear cumulative damage theory.The life of the bogie frame was estimatesd in the two theories.The results show the frame satisfied the12million safety operation requirement and the life estimated in Corten-Dolan’s theory was more conservative than that in Miner’s linear cumulative damage theory;The equivalent stress’s change with mileage of different measuring points were studied.Fifthly,analyze effects of different working conditons and speeds on dynamic stress.With the frequency-speed-energy relation diagram, the sources of main frequency energy were detected when the train was in acceleration phase,uniform phase and deceleration phase.Finally the main factors that affect the bogie’s vibration were found out.