抽油杆扳手方缺陷应力集中系数和容限

针对抽油杆扳手方部位经常出现引发断裂的各种缺陷的情况，建立了横向凹槽、平面凹坑和边棱凹坑三组有代表性的缺陷模型，利用平面模型有限元法计算结果及受拉伸无限体和半无限体旋转椭球面空洞和凹坑应力集中系数，求得近、远边界影响修正系数以及三组不同缺陷模型应力集中系数近似表达式。用三维趋势面图描述了这些应力集中系数的变化规律，求得各组缺陷容限方程，绘制了典型的容限图，为带缺陷抽油杆的修复使用和判废提供了理论依据。

Stress concentration factor and tolerance of flaws on sucker rod wrench square

In the light of the flaws on the rod wrench Square, three groups of trpical flaw models, i. e. the cross groove model,plane groove model and edge pit model, are established, the "modifying coefficient affected by near boundary" and "modifying coefficient affected by far boundary" are worked out by means of the results of finite element calculation with the plane model and the relevant calculating results of stress concentration factors, thereby the approximate expressions for the three groups of flaw models are obtained, and the variation pattern of the stress concentration factors is described by the three-dimensional trend diagram. The tolerance equations for every group of flaw are derived, and typical tolerance diagram is given.