摘要
Goodman-Smith曲线在轨道车辆疲劳评估中应用广泛,但UIC ORE B12/RP17标准中提供的Goodman-Smith曲线在使用过程中存在安全裕量不高和焊缝数据缺乏合理性的问题。本文首先分别采用UIC标准中提供的Goodman-Smith曲线和BS 7608标准对3种典型焊接接头模型进行疲劳强度评估,证明Goodman-Smith曲线评估的结果较为宽松。其次,为使Goodman-Smith曲线能够适应实际情况出现的非对称循环载荷,提出非对称循环疲劳强度向对称循环的转换公式,实现BS 7608标准中脉动循环向Goodman-Smith曲线所需对称循环的转换。然后,根据BS 7608标准提供的S-N曲线修正循环次数为2×10^(6)次下的对称循环疲劳强度,并结合UIC标准,绘制改进后的八边形Goodman-Smith曲线。最后,分别改进前后的Goodman-Smith曲线对某转向架构架的关键焊缝进行疲劳强度评估。结果表明,改进后的Goodman-Smith曲线可以有效解决安全系数过大导致的疲劳评估结果过于宽松以及焊缝数据缺乏合理性的问题。该设计改进的曲线更加符合工程应用需求,为转向架构架焊接结构评估方法提供了新参考。
Goodman-Smith curves are widely used in the fatigue assessment of rail vehicles.However,the Goodman-Smith curves provided in the UIC ORE B12/RP17 standard have the problems of insufficient safety margins and inadequacy of weld data during practical usage.To this end,this paper first used the Goodman-Smith curve provided in the UIC standard and BS 7608 standard for fatigue strength assessment of three typical welded joint models,respectively.The results of the Goodman-Smith curve evaluation are proved to be more relaxed.To make the Goodman-Smith curve adaptable to the asymmetric cyclic loading that occurs in real situations,the conversion formula of asymmetric cyclic fatigue strength to symmetric cycles is proposed to realize the conversion of pulsed cycles to symmetric cycles required by the Goodman-Smith curve in BS 7608.The symmetrical cyclic fatigue strength at 2×10^(6)cycles is then corrected according to the S-N curve provided by BS 7608.And combined with the UIC standard,the improved octagonal Goodman-Smith curve was drawn.Finally,the fatigue strength of the key welds of a bogie frame was evaluated by improving the Goodman-Smith curves before and after the weld.The results show that the improved Goodman-Smith curve can effectively address the issues of overly lenient fatigue assessment results and lack of weld data adequacy caused by overly large safety factors.The design improvement curve aligns better with the engineering application requirements and provides a valuable reference for evaluating bogie frame welding structures.
作者
王悦东
田博雅
何紫薇
Wang Yuedong;Tian Boya;He Ziwei(Key Laboratory of Railway Industry on Safety Service Key Technologies for High-speed Train,Dalian Jiaotong University,Liaoning,Dalian 116028,China;Beijing Railway Administration,China Railway Beijing Group Co.,Ltd.,Beijing 102600,China)
出处
《铁道技术标准（中英文）》
2023年第9期1-7,共7页
Railway Technical Standard(Chinese & English)
