膨胀管非线性大变形过程中摩擦问题模拟研究

Simulation research on the friction problem with the nonlinear large-deformation of the expandable tube

膨胀管的膨胀过程属于非线性大变形过程,其接触摩擦问题用一般方法很难求解,依据修正的库伦摩擦定律,结合套管大变形问题的增量分析过程,用数值模拟方法详细分析了在不同摩擦因数下套管膨胀后套管的壁厚变化规律、等效应力变化规律以及轴向收缩量变化规律。选用ANSYS模拟分析技术,采用114mm×7.34mmAPI标准的N80套管,将内直径从99.32mm扩张到119.20mm。分析结果表明,在相同膨胀锥使套管膨胀的情况下,不同摩擦因数对套管的力学性能存在较大影响,摩擦因数越小,膨胀后套管残余应力越大;套管膨胀时,必须综合考虑膨胀过程中壁厚的变化、轴向收缩量的变化、膨胀后残余应力的变化,从而合理选择润滑措施。

The expansion of the expandable tube is a kind of nonlinear large-deformation process.Its contact friction problem cannot be solved by ordinary methods.According to the revised Coulomb friction law and referring to the increment analysis on the problem of casing large-deformation,the numerical simulation method was adopted to analyze the change law of the wall thickness,equivalent stress and axial shrinkage after the expansion of casing under different friction factors.The ANSYS simulation analysis technology was applied,the standard API N80 casing of φ114 mm×7.34 mm was adopted and the internal diameter of 99.32 mm was enlarged to 119.20 mm.The analysis shows that,under the condition that the same expansion cone makes casing expand,different friction factors have great effect on the mechanical performance of casing.The smaller the friction factor,the greater the residual stress after the expansion of casing.When casing is made to expand,the change of the wall thickness and axial shrinkage in the process of expansion as well as the change of residual stress after expansion should be considered in an overall way so as to choose proper lubrication measures.