Strength Analysis And Fatigue Life Estimation Of Weld Line On The Parts Of Freight Car Wheels With Heavy Axle Load

Rapid economic development in some areas of our country has been hampered at a certian extent by the capability of our railway freight transportation. Therefore, it is urgent to develop the freight car wheels with heavy axle load. Fatigue crack at welded area has been found in the process of overhauling during freight carbody that has been put into use, and it becomes a significant threat to the safe operation of heavy vehicles.In this paper, the fatigue life of armor steel Tee joints are analyzed by nominal stress method and structural stress method.Comparing with the test, the results show that the structural stress method is provided with the insensitivity characteristics of the element. Computing results according to the structural stress method are closer to experimental value.First of all, a finite element model of bogie frame for strength analysis is built, five computation loads under exceptional in-service loads and eight computation loads under normal in-service loads are determined according to TSI standards. The design requirements in static strength and fatigue strength could be met in the final plan after analysis.Secondly, a finite element model of bogie frame for fatigue life analysis is built. Based on structural stress method, fatigue life at 21 key welds of bogie frame is predicted according to fatigue loads of TSI standards.The result shows that 4 welds of these 21 key welds in carbody bolster are short fatigue life, because of incongruous stiffness and stress concentration.Thirdly, a finite element model of carbody of coal gondola car for fatigue life analysis is built. Based on structural stress method, fatigue life at 33 key welds of carbody is predicted, the carbody supportted vertical load spectrum, longitudinal load spectrum and body torque load spectrum, which are picked from AAR Standards. The result shows that 5 welds of these 33 key welds in bogie beam are short fatigue life, because of incongruous stiffness and stress concentration.Finally, local structure is improved according to the structural stress distribution along weld line in carbody of coal gondola car and weld frame of bogie. The fatigue life of weld line on improved structure is increased.