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为了对出口缅甸3B_0机车转向架焊接构架的疲劳寿命进行预测,采用有限元方法对构架在不同疲劳载荷下的应力状态进行分析,确定了箱体梁中主焊缝的多种疲劳应力范围。基于IIW标准和相关文献中焊接接头疲劳寿命数据确定了评估焊接构架的多条S-N曲线方程,在此基础上采用整体名义应力法和局部缺口应力法计算了关键主焊缝的寿命次数。结果表明:所有焊缝的寿命次数均大于2×10~6次,满足轨道车辆焊接接头设计标准要求;其中构架侧梁T型角接头在垂向动载作用下寿命较低,应通过焊缝磨削处理降低其应力集中程度。由于名义应力法分析结果较缺口应力法更为保守,从结构轻量化和局部优化角度出发,采用局部缺口应力进行焊接结构疲劳寿命预测更具有优势。
In order to predict the fatigue life of the welded frame of 3B_0 locomotive bogie exported to Myanmar, the finite element method was used to analyze the stress state of the frame under different fatigue loads, and various fatigue stress ranges of the main weld in the box girder were determined. Based on the IIW standard and the fatigue life data of the welded joints in the related literature, several S-N curve equations of the welded structure were determined. Based on this, the number of lifetimes of the key welds was calculated by using the global nominal stress method and the local notched stress method. The results show that the lifetimes of all welds are more than 2 × 10 ~ 6 times, which meets the design standard of welded joints of rail vehicles. The T-joints of frame side beams have low life under vertical dynamic load and should pass through the weld Grinding reduces its stress concentration. As the result of nominal stress analysis is more conservative than the notched stress method, it is more advantageous to predict the fatigue life of welded structure by using local notched stress from the perspective of structural lightweight and local optimization.