Abstract: The problems that the parameters are unreasonable and the reliability is not considered in conventional fatigue strength design and API design are presented,the random working stress in sucker rods is analysed and the corresponding treatments are provided.The method for determining fatigue limit distribution in sucker rods is put forward.Under the prerequisites of known the stress distribution in sucker rods and the fatigue strength distribution at a given stress ratio,the equivalent fatigue strength distribution in sucker rods at any stress ratios is given and a method for calculating the fiducial level of fatigue strength of sucker rods by using a stress－strength interference model is offered.

Key words: sucker rod, fatigue strength, reliability

摘要： 提出了常规疲劳强度设计方法和API设计方法中存在的参数不合理且无可靠性指标的问题;分析了抽油杆承受的随机工作应力并给出了处理方法;提出了抽油杆疲劳极限分布的确定方法;在已知抽油杆应力、一定应力比下的疲劳强度分布的前提下,得出了抽油杆在任意应力比下的当量疲劳强度分布,并利用应力-强度干涉模型提出了抽油杆疲劳强度的可靠度计算方法.

关键词: 抽油杆, 疲劳强度, 可靠性