非API标准工况下套管接头的强度分析

Strength analysis of casing connections under nonAPI normal cases.

将５″１７ｌｂ／ｆｔＪ５５ＡＰＩ８ＲＬＴＣ长圆螺纹套管接头作为研究对象，考察其在非ＡＰＩ标准工况下的强度。建立了力学模型和有限元计算模型，并对计算结果进行了分析。分析结果表明，应用轴对称体接触问题的半解析有限元法，可以有效地解决非ＡＰＩ标准工况下套管接头力学特性这类复杂的接触问题，与纯三维问题相比，这种方法大大缩减了自由度；在弯曲作用下，接头螺纹啮合段环向０°位置处的等效应力增大，环向１８０°位置处的等效应力减小，并且这种变化随弯矩载荷的增大而增大，而环向９０°和２７０°位置处的等效应力变化很小；在非均匀挤压下。

The strength of casing connections is analyzed by means of the semianalytical finite element method for the contact problem of axisymmetrical body.By taking round thread casing connections as objectives for investigation,the strength of the connections under nonAPI normal casings is observed,relevant mechanical model and finite element calculation model are established,and the calculated results are analyzed.Analysis results show that,the abovementioned method can be used to solve effectively the complicated contact problem of the casing connections with decreased degree of freedom,and under the action of bending moment,the equivalent stress in the position of 0 round angle of the engagement section increases and that in the position of 180 round angle decreases,while the equivalent stresses in the positions of 90 and 270 round angles of the engagement section vary slightly;under the action of nonuniform extrusion,the maximun equivalent stress occurs in the direction of minor extrusion.