双台肩钻杆接头上扣扭矩力学特性分析

Mechanical Behavior of Double Shoulder Tool Joint Under Make-up Torque

为研究ø139.7 mm×9.17 mm IEU S135特殊螺纹钻杆接头的上扣力学特性,建立了包含进、退刀槽结构的双台肩钻杆接头三维非线性有限元模型,考虑材料非线性、结构非对称、螺旋升角和各啮合面接触等因素,采用ABAQUS/Explicit有限元方法对上扣扭矩作用下钻杆接头关键结构的应力分布特性进行分析。研究结果表明:钻杆接头整体等效应力分布不均,在横截面内呈轴对称分布,关键结构处应力集中显著,最大等效应力未超过材料屈服强度;钻杆接头台肩上的径向预留间隙和其过渡圆角处的结构非连续对台肩面的等效应力及接触压力分布影响显著;钻杆接头螺纹段的等效应力和接触压力均呈“U”形分布,应力整体分布均匀,螺纹接头前3扣与后3扣的承载比之差为8.6%,表明接头承载性能较佳。对有限元模拟结果进行实物验证试验对比分析,试验结果与有限元模拟结果基本符合。分析结果可为钻具优化设计及安全应用提供数据支撑。

In order to study the make-up mechanical behavior ofø139.7 mm×9.17 mm IEU S135 special threaded tool joint,a 3D nonlinear finite element model of double shoulder tool joint with engage and retract groove structure was built.Then,taking into account the factors such as material nonlinearity,structural asymmetry,helix angle and contact of each engagement surface,the ABAQUS/Explicit finite element method was used to analyze the stress distribution of the key structure of the tool joint under the action of make-up torque.The results show that the overall equivalent stress distribution of the tool joint is uneven,with an axisymmetric distribution within the cross section,obvious stress concentration at key structures,and the maximum equivalent stress does not exceed the ma-terial yield strength.The radial reserved gap on the shoulder of tool joint and the structural discontinuity at its tran-sition fillet have a significant influence on the equivalent stress and contact pressure distribution on the shoulder surface.The equivalent stress and contact pressure of the threaded section of the tool joint are both distributed in a“U”shape,the overall stress distribution is uniform,the difference between bearing ratios of the first three threads and the last three threads of the threaded joint is 8.6%,indicating that the joint has good bearing performance.The finite element simulation results were further compared and analyzed by physical verification test,indicating that the test results are basically consistent with those of finite element simulation.The analysis results provide data support for further optimal design and safe application of the drilling tools.