Structure Reliability Analysis Of The EMU Bogie Frame

As the EMU running in all parts of our country,people pay more attention to its reliability and safety.The bogie frame is a key part of the EMU running gear.It is not only the installed base of the other parts of the bogie,but also the main carrier of the car body weight.In order to guarantee the reliability and safety of the EMU,it is necessary to do the structure reliability analysis of the bogie frame.Considering complex structure and random parameters,the RSM is used to fit out the relationship between the input variables and output response.Then the structure reliability analysis of the bogie frame can be finished.The main contents are as follow:(1)Structure reliability analysis of the bogie frame.Firstly,the finite element model of the bogie frame is established by HyperMesh.Then static strength analysis of the bogie frame is finished based on UIC standards.By comparing the maximum Von.Mises stress of the frame with allowable stress of the material of the six load steps,we can judge the structure is safety or not.The structure reliability analysis of the bogie frame can be finished under the load step which has the largest Von.Mises stress.The limit state equation can be established base on the evaluation standards.When the maximum Von.Mises stress is less than the allowable stress,the structure is reliable.The RSM is used to fit out the relationship between the input variables and output response.By using the ANSYS/PDS,the structure reliability analysis of the bogie frame can be finished.(2)Fatigue reliability analysis of the bogie weld.A fatigue reliability analysis method is given based on the UIC standard,BS standard,Miner's cumulative damage theory and ANSYS/PDS module.The randomness of the factors such as fatigue stress and material property are considered through this method.By using the APDL language,the automatic program of fatigue reliability analysis is developed.Put the program into the analysis file and the fatigue reliability analysis of the bogie weld can be finished by the ANSY/PDS.The standard of the fatigue analysis is:when the weld fatigue damage is less than 0.6,the structure is reliable.(3)Fatigue reliability analysis based on orthogonal RSM.Based on the Fatigue reliability analysis in part two,the orthogonal design and the RSM are put together.By this way,the choosing process of the RSM can be optimized.A program which can automatically generate the sampling file is developed.This program can save the analysis time and avoid unnecessary mistakes.Based on the sampling file.RSM and ANSYS/PDS module,the fatigue reliability analysis can be finished.(4)Structure reliability optimization of the bogie frame.Based on the structure reliability analysis.the structure reliability optimization of the bogie frame is finished in this part.In order to reduce the material redundancy and ensure the reliability of the frame,several panel parts which have a large or small local stress are chosen as the optimized object.And the optimization goal is to make the thickness of panel parts as small as possible.By using APDL language,the parameter model is established.The relationship between the input variables and output response can be fit out by using samples from the experiment design.In the condition that the maximum stress of the frame is less than 295MPa,the structure reliability optimization can be finished.