环肋加劲压力钢管的有限元屈曲分析

摘要

The penstocks are vulnerable to instability under external loads. In order to study the critical buckling value of ring stiffened penstocks ,linear buckling and nonlinear buckling analysis of penstocks were completed by using the finite element software ABAQUS with taking a hydroelec-tric power station penstock as an example in considering the large deformation of the steel penstocks and on the basis of initial imperfection . The re-sults show that the finite element method can reasonably consider interactions with ring stiffener and penstock segment between stiffeners ,and FEM is more reasonable than the specification design method and Amstutz’s approach ,which are separately considering the stability under external pres-sure of ring stiffener and middle pipe segment. In view that the stiffened ring can significantly improve the stability of penstocks,suitable ratio of height to thickness for stiffener is under study,in order to providing reference for using of penstock normative design method.%压力钢管在外压下极易失稳，为了研究环肋加劲压力钢管的屈曲临界载荷，以某二级水电站压力钢管的下平段为例，基于结构屈曲理论，利用有限元软件ABAQUS分析了钢管的线性屈曲情况，在此基础上考虑钢管的大变形及初始缺陷，分析了钢管的非线性屈曲情况。结果表明，有限元法可以合理地考虑加劲环和管壁的相互作用，比规范法、阿姆斯图兹法单独考虑加劲环管段和中间管段的外压稳定更加合理。鉴于加劲环可显著提高压力钢管抗外压稳定能力，还研究了加劲环局部稳定适宜的高厚比，以期为更好地使用规范提供参考。