抽油杆柱疲劳断裂失效分析

Fracture Failure Analysis of the Sucker Rod

在交变载荷作用下,存在张开性裂纹的抽油杆柱极易发生疲劳断裂。结合抽油杆典型的疲劳失效形式,分别利用材料的应力强度因子和临界尺寸计算原则,分析了20CrMo钢D级抽油杆在Goodman载荷下的表面缺陷临界尺寸及杆体局部表面缺陷门槛尺寸。为了确保抽油杆柱的使用寿命,提出杆体环形表面缺陷门槛尺寸应不小于0.1mm的设计原则。

Under the alternate loading, sucker rod with opening crack easily causes fatigue frac- ture. Combined with the sucker rod typical fatigue failure forms,the stress intensity factor and the critical dimension calculating two principle conditions of the material was used to calculate the fa- tigue failed in this article. The critical dimension of surface defect and the surface defect threshold dimension in local region of the most common form of sucker rod with 20 CrMo steel grade D were computed under the Goodman load. In order to ensure the sucker rod working life, the design dimensions of the sucker rods annular surface are not less than the threshold dimension O. 1 mm in the design process.