Fatigue Life Study On Key Parts Of Bogie Frame By Hot Spot Stress Method

Widely absorbed some new advantages of mechanical structure fatigue of the domestic and abroad, lots of researches on fatigue problem about the local structures of bogie frame are done in this thesis. The main objective of this research is to explore a method to solve the fatigue design problem about the local structures of bogie frame.The main aspects studied in this paper are as follows:1. Using FEM of structure, the key parts of a bogie frame steel structure mechanics model are constructed, and the FEM static strength analysis is done. Using multi-body system dynamic software SIMPACK, dynamic modal of locomotive structure is established in detail. Under the given track excitation, through calculation, loading-time history is obtained. Then the result of analysis of FEM and that of dynamics are combined. Together with the S-N curve of the material, fatigue analysis software FE-Fatigue is used to forecast the fatigue life of the vertical damper hold. Using hot spot stress method, the same model is analysed to forecast the fatigue life. The results of the two methods are compared, and it shows that hot spot stress method is the better one.2. Fatigue life of the vertical damper hold is forecasted to study the influence of some factors such as the finite element style, the mesh size near the weld toe during the hot spot stress method analysis.3. Submodel is used during the hot spot stress method analysis on the horizontal damper hold of a bogie frame. The damper hold is analysed before and after adding the bogie frame mean stress. The results are compared to get the influence of bogie frame mean stress to the hot spot stress method.4. The influence of different seam angles and plate thicknesses to the hotspot stress method is studied by forecasting the fatigue life of a traction seat.Using hot spot stress method, welding seam fatigue life prediction of the bogie frame is compared and researched. These efforts may provide a method to forecast and check the welding seam fatigue life of the locomotive local structures.