The Research of Fatigue Life Prediction of Welded Structures for the Freight Train
|School||Dalian Jiaotong University|
|Keywords||Freight Train Welded Structure Equivalent Structure Stress Method Fatigue Life Prediction|
Welding is the main connection of railway vehicles, Railway Vehicle basically welded sheet metal, which contains a variety of joint type, joint type structure, the more the more complex. Practical application experience has shown that the destruction of welded structures for the fatigue failure of 90%. In addition, during the operation of railway vehicles, the body is exposed to the random force is a continuous process, welding parts of the stress state becomes very complicated, mechanics of materials, methods of elasticity becomes very difficult to solve, in this, the use of computer use "virtual simulation" theory of the combination, and fatigue is particularly essential to its analysis.In this paper, fatigue assessment standard include International Welding Association IIW standard、United Kingdom steel BS standard. United States AAR standard and Goodman curve method which are widely used in the current internationa are introduced firstly,then equivalent structural stress method are also introduced,the equivalent structural stress method is a new prediction technology of welded structure fatigue life,it is named as master S-N curve method of grid insensitivity. Fatigue life prediction of weld structure of C80b steel body which is main used for transporting coal were carried out through above fatigue method and standard and use the corresponding load spectrum of AAR standard. The advantages and disadvantages are analyzed between several standards and methods to results which are got based on above standard. Finally fatigue analysis of common welded joints has been completed to railway cars based on the equivalent structural stresses method, then combined with some practical application instances of the equivalent structural stress measures which can improve fatigue stress of welded joints are given.In this paper, railway vehicle as a research object and through compare results and processes a variety of standards,we draw some features of various kinds standards in process of applying.Then some measures which can improve fatigue stress of welded joints are given and provide a reference for the fatigue design of railway vehicles.