Design Fatigue Reliability Analysis Of The Welded Jionts Around The Connections Of CRH2EMU Bogie Frame With Belongings

Fatigue reliability is investigated for the welded joints around the connections of CRH2bogie frame and belongings.The probabilistic fatigue S-N curves and Goodman-Smith diagrams are firstly constructed by the previous Zhao et al methods for the lateral butt welded joint, lateral T welded jiont, and longitudinal T welded joint from the former test data of Q345welded joits. In the process, symetrical treat is made to stress amplitude. The Goodman-Smith diagrams have covered three fatigue lives of107cycles,108cycles and109cycles. In addition, shear stress Goodman-Smith diagrams is also constructed under consideration of a transferring ratio relationship between tension strength and shear strength.Local stresses of31locations dealing the welded joint around the connections are gotton from former calculations of our team for the frame. Fatigue calibration is made for locations with bigger fatigue stresses using the above Goodman-Smith diagrams. And the fatigue life prediction and reliability evaluation are performed using the probabilistic curves. Results reveal that the joint close to connection of gear box on the frame lateral beam is a hot location, which has a life of3.88×10cycles under confidence of97.5percent and a survival probility of0.975; a survival probily of0.9482under confidence of97.5percent and a requirement of life of109cycles.