Fatigue Life Prediction Of A Railway Locomotive Bogie Frame

For a long time, bogie frame as a key structural component of railway vehicle system, the structural strength and fatigue life are widely concerned. The intensity of a frame can be ensured by the calculation combining with the corresponding theory at the design stage. The frame fatigue life assessment under dynamic loads is done by adopting fatigue test only after the completion of the manufacture. If the testing results show that the fatigue strength of this type frame doesn't satisfy design requirement or service life, the frame should be improved or redesigned. It's obviously incompatibe with modern design concepts which must shorten product development cycles and minimize the manufacturing cost.Based on the latest fatigue research results at home and abroad, the paper is to achieve the locomotive bogie frame fatigue life assessment via the Multi-Body system dynamic simulation, the finite element method and fatigue life prediction at the design stage. Firstly, the whole locomotive dynamic model was established using the SIMPACK software according to the actual structural parameters. All the load histories, which were used to evaluate the bogie frame fatigue life, would be obtained by the dynamic performance simulation under the typical locomotive operation condtions. Secondly, the solid model of the frame was established using the 3D software SolidWorks. The finite element analysis of the frame was achieved through the connection between the 3D software and ANSYS software, including the static stress analysis, quasi-static stress analysis and modal analysis. Finally, combining the S - N curves of the material and weld, the load histories acting on the frame and the results of the quasi-static stress analysis, choosing the appropriate fatigue life prediction method, the frame fatigue life evaluation was done using the nSoft software. The most weakness position was confirmed and then the particular fatigue life analysis was done.The above fatigue life prediction method based on the virtual techinique can predict the stress distribution at the design stage and provide the theory instruction for the structural optimization of the frame.