可膨胀筛管外壳膨胀性能的数值分析

 为提高保护外壳的膨胀性能，提出了圆形波纹管形式外壳的设想，并采用非线性有限元方法分析了其膨胀性能。数值计算结果表明，圆形波纹管可以实现较小的应力和较大的位移补偿。外壳的波纹半径与其膨胀性能紧密相关，波纹半径制约着外壳的膨胀均匀度和圆度以及施工难易程度，随着波纹半径的增加，膨胀力和膨胀后的不圆度减小，但膨胀后与套管内壁的接触面积也随之减少，波纹管的合理波纹半径应为8～14 mm。波纹管壁厚对其膨胀力和应力储备系数的影响均不大，但制约了可膨胀筛管的外径和内部构件的尺寸，可膨胀筛管外壳波纹管的合理壁厚为2 mm。

Numerical analysis on expandable ability of expandable screen shell

To enhance expandable ability of expandable screen shell, a circular bellow shell is designed and its expandable ability is analyzed by non-linear FEA method. Result of numerical calculation indicates that this circular bellow shell has small stress but large displacement compensation. The bellow radius has close relation with its expandable ability. The former restricts its expandable symmetrical degree and its easy-manufacture ability. With the increase of bellow radius, expandable force and non-roundness, as well as contact area between sleeve and shell, decrease. The reasonable bellow radius is 8-14 mm. Moreover, the thickness of shell has little impact on expandable force and stress storage coefficient, but it restricts the outside diameter of expandable screen and the size of inside accessory. The reasonable thickness of shell is 12 mm.