Strain Modal Analysis And Improvement Of High Speed Train Frame

Nowadays Chinese railway has entered the fast development stage, and High Speed Multiple Unit has gained wide attention. The dynamic performance of bogie is an important manifestation of operation performance and plays an important role on the train design. The bogie is the locomotive driving the vehicle and running gear, thus it is one of the critical components to make train safe and smooth during operation. Structural strength characteristics, fatigue characteristics and dynamic characteristics are directly related to safety of the high-speed train. The frame is the key component of the high speed train bogie, the research on the strength, fatigue strength and vibration capability is the pivotal part in the vehicle design over the world, the CRH380A bogie frame was taken as a research object in this paper to test the frame’s dynamic characteristics were studied and its fatigue strength was evaluate the main work includes three parts:Firstly, finite element simulation analysis was applied to the framework to understand the dynamic characteristics and obtain strain modal vibration mode, based on the analysis of the harmonic response to harmonic excitation of the vibration of the framework, the thesis finds out the resonant frequency various hazardous area of the framework.Secondly, we carried on on-line test and collected a lot of data, 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, the main factors that affect the bogie’s vibration were found out. The frame modal parameter was identified by stochastic subspace method, comprising resonance frequency, ratio of damping and vibration form. The results of experimental modal identification can be used to verify the finite element model, which can provide reference and basis for the design of dynamic characteristics of the structure.Thirdly, results of experimental modal identification may be used to verified the finite element model of the frame, the first-order mode of frame is improved which played an active role in avoiding resonance. The maximum deformation and maximum stress are aslo met intensity requirements. Ultimately optimize bogie frame structure and reduce costs consumption to achieve the purpose of dynamic performance.