Study The Fratigue Base On The Crack Of 209P Bogie Frame

Railway Transport is characterized by high degree of safety, powerful transportation capacity, lower transporting cost, fast speed, little contamination to the environment and resistant to adverse climatic conditions. It is an indispensible means in modern transportation. With the growth of economy and the increasing mobility of population, railway transport is increasingly under greater pressure. With the construction of high speed trains, the running speed and the weight of trains will continuously increase, and the problem of trains’vibration will become more and more prominent. Different factors contribute to the vibration of trains, including track irregularity intensifying the vibration between wheels and rails; vibration of the pantograph-ocs system; the dynamic interaction between the train and air. These factors will cause fatigue damage, hence resulting in fatigue failure of equipments and decrease of the safety of train structure.The thesis employs the finite element simulating software to simulate 209P bogie, and makes predictions about the vibration fatigue life of 209P bogie on the condition of uneven rails and random excitation. The thesis has both practical and theoretical significance in that the thesis makes a comparison between different stress values on the dangerous part of 209P bogie frame with various inertia forces. A dynamic simulation of the 209P bogie is also made and an analysis of causes for cracks resulting from the running of the bogie in transportation.The thesis, depending on the rail testing data of passenger trains with 209P bogie collected by the national key laboratory of railway motive power in Southwest Jiaotong University, studies the random vibration fatigue life of 209P bogie frame. The thesis examines the following aspects:1. The thesis introduces methods used to analyze random vibration fatigue life, and elaborates and compares time domain method and frequency domain method included in time domain method. In accordance with the characteristics of time domain method and frequency domain method, a proper method can be selected to make an analysis of vibration fatigue life.2. Depending on the real track data, finite element simulation is made on 209P bogie frame and a modal analysis is made on 209P bogie frame. And then utilize the data and Gauss three interval method to calculate the vibration fatigue life of frame, and compare stress in dangerous part under different inertia force.3. Establish dynamics simulation model of 209P passenger trains. By means of dynamic simulation hunting unstable frequency and force on frame by the wheels can be obtained. A discussion about the effect of equivalent taper and the gape of location bush on the critical speed of the frequency of haunting instability in the vehicle system.