高速客车转向架构架焊接接头疲劳可靠性分析
Fatigue Reliability Analysis of Welded Joints for Bogie Frame of High-speed Passenger Car

为研究构架焊接部位的疲劳可靠度，根据国内Q345焊接头的疲劳数据，结合包含超长寿命概率S-N曲线，建立了动车组转向架焊接构架横向对接、横向T形和纵向T形焊接头的概率疲劳S-N曲线。以我国高速动车组典型的CRH2动车组转向架构架为研究对象，确定了其焊接构架吊挂点附近31个焊接头局部的疲劳应力。结合概率疲劳S-N曲线进行了较大应力部位的疲劳寿命预测和可靠度评估。结果说明：齿轮箱吊座与横梁附近的焊接部位是较危险的部位；在置信度97.5%、可靠度0.975下的寿命为3.88×108循环；在置信度97.5%、寿命为109循环的可靠度为0.948 2。
In order to investigate the fatigue reliability of the welded position in bogie frame, with the methods the probabilistic fatigue S-N curves are constructed for the lateral butt welded joint, lateral T welded joint, and longitudinal T welded joint from the former test data of Q345 welded joints. For the high-speed bogie frame of passenger car, the bogie of CRH2 EMU is selected as the research object. Local stresses of 31 locations for welded joints around the connections are obtained from former calculations for the frame. Fatigue life prediction and reliability evaluation are performed with the probabilistic curves. The results reveal that the joint close to connection of gear box on the frame lateral beam is a critical location, which has a life of 3.88×108 cycles under a confidence of 97.5% and a survival probability of 0.975; if a life of 109 cycles is required under the same confidence level, the survival probability decreases to about 0.948 2