圆螺纹套管的滑脱机理研究

连接接头滑脱失效是圆螺纹套管损坏的主要形式。利用弹塑性有限元法，研究了圆螺纹套管接头发生滑脱失效的过程与机理，然后通过全尺寸试验，分析了这种接头在失效过程中的应变分布及变形情况，并验证了有限元结果。研究表明，圆螺纹套管滑脱失效最先发生在啮合大端的第1、2牙螺纹上，设法提高此处螺纹的承载能力，对提高圆螺纹套管的连接强度具有重要意义。

Pull-out Failure of Round Thread Casing Connections

Pull-out failure is the main damage form of round thread casing connections. The pull out failure and mechanism were studied in detail with elastic plastic finite element method, and then full-scale tests were performed to show the joint strain distribution and deformation during pull-out process, and validate the FEA results. The study showed that pull-out failure occurs at the first and second meshed teeth near coupling end at first. Increasing the load capacity of these two teeth can improve the joint strength notably.