Study On Quality Evaluation Method Of Welding Seam Grade Of Bogie

With the rapid development of China’s railway transportation in recent years,rail transit has gradually become one of the most important ways for the public to travel.With the opening of urban rail transit in various major cities in China,people’s requirements on the safety,stability,comfort and other aspects of subway vehicles are also increasing.As one of the most important components of subway vehicles,the rationality of bogie structure design directly affects the stability,safety and dynamic performance of subway vehicles.Therefore,the research on bogie structure is of great significance for the design of subway vehicles.Taking a certain subway bogie as the research object,this paper analyzes its static strength,mode,fatigue strength,etc.,in order to explore whether the structural design of bogie frame meets the safety requirements.On the basis of analysis,this paper studies the determination method of weld detection grade.This paper mainly focuses on the following parts:Firstly,it introduces the basic theory of fatigue analysis,the basic characteristics of welded structure fatigue and the factors affecting the fatigue life of welded structure,and expounds the basic content and checking process of British BS7608 standard and German DVS1612 standard.Secondly,the relevant standard EN15085 for weld inspection grade definition is introduced.The fatigue life calculation comparison of two types of welded joints is conducted based on BS7608 and DVS1612.On this basis,the research on weld inspection grade is carried out using the standard EN15085.Thirdly,processing before using finite element software Hyper Mesh metro bogie frame model geometry processing and meshing,and establish the finite element model based on UIC615-4 the bogie frame structure strength test standard to determine the required conditions,combined with the fourth strength theory to calculate the bogie frame static strength under the condition of safety coefficient,in order to study the safety of the truck frame.Then,the theory of modal analysis is introduced,and the modal analysis of bogie frame is carried out by using ANSYS software.Through the analysis of vibration frequencies and modes of each lower order,the conclusion is obtained that the natural frequency of the steering mechanism frame is higher than the vibration frequency of the subway vehicle and the vibration frequency of the track,which effectively avoids the phenomenon of resonance.Finally,based on DVS1612 standard and EN15085 standard,fatigue strength analysis and weld performance grade of subway bogie are studied.Based on standard UIC615-4 applied load conditions,according to the standard research key parts in truck frame DVS1612 weld fatigue life,and based on EN15085 standard to confirm the safety level of the bogie frame of the key weld,weld performance level,the weld inspection level important reference indexes,such as the results of the study for rail vehicles and components such as the welding joint of welded structure design and evaluation provides a theoretical basis.