中文摘要：

钻杆接头是钻柱最薄弱的环节,在钻进过程中极易失效。采用有限元分析方法对钻杆接头的应力特征进行了分析,结果表明,密封面处接触压力分布不均和啮合大端第一螺纹牙处应力集中是影响钻杆接头力学性能的主要因素。在公扣、母扣台肩转角处开应力释放槽可以有效改善钻杆接头的应力分布,降低应力峰值,使von Mises应力和接触压力分布更加均匀,有利于提高钻杆接头的承载能力和密封性能。此外,仅在公扣台肩转角处或母扣台肩转角处开应力释放槽也可有效改善接头的应力分布,但效果与公扣、母扣台肩转角处均开应力释放槽相比稍差。

英文摘要：

Drill pipe joints,the weakest part of drill string,are prone to fail during drilling.This paper analyzes the stress characteristics of the drill pipe joints using finite element method.The results indicate that uneven distribution of the contact pressure on the sealing surface and the stress concentration on the first threads are the main factors that reduce the drill pipe joints＇ mechanical performance.A stress relief groove at the shoulder corner can effectively resolve these problems.The stress of joints is uniformed and the peak of stress is reduced with a stress relief groove,which improve the bearing capacity and sealing performance of drill pipe joints.Furthermore,machining a stress relief groove only at the corner of pin＇s or box＇s shoulder also can effectively improve the mechanical performance of drill pipe joints.