受横向约束的细长无重管柱在压扭组合作用下的后屈曲分析

ANALYSIS OF POST-BUCKLING OF LATERALLY CONSTRAINED LONG WEIGHTLESS TUBING SUBJECT TO AXIAL AND TORSIONAL LOADS

井眼中管往的屈曲，将会使钻井、采油生产等作业难以顺利进行，弄清管柱屈曲后的特性对石油工程有重要的实际意义。本文首先建立了受横向约束的管往在轴向载荷和扭矩的作用下的屈曲平衡方程；并对所得四阶非线性常微分方程进行了分析、求解。结果表明，在特定边界条件下，受压扭组合作用的管柱屈曲构形为精确的圆柱螺旋线；并进而得到了管柱屈曲变形与载荷之间的解析关系；本文结果退化后与文献所得结果一致；最后讨论了管柱所受扭矩对螺旋屈曲行为的影响和扭矩对螺旋旋向的影响。

The equilibriUm equation for a long weightless buckled tubing in straight well under axial thrust and torsional moment is developed, The fourth-order strongly nonlinear ordinary differential equation is directly solved. The results show that the post-buckling configuration of the tubing under some idealized conditions is an exact belieal shape. An analytical solution for the relation between load and pitch has been determined. The influence of torsional loads on post-buckling of tubular in well bores, especially on the tubing spirals to the right or left, has been discussed. The degeneracy of the analytical results is coincident with those given by others using energy method.