考虑弯矩作用梭形钢格构柱的稳定性能

通过弹性屈曲分析和考虑大变形的弹塑性非线性分析首次考察轴力和弯矩共同作用下梭形钢格构柱的稳定性能。首先提出梭形格构柱截面刚度变化率的概念并分析其弹性屈曲性能,进而考察弯矩作用对梭形格构柱稳定性能的影响,重点分析轴向应力、弯曲应力和剪应力的发展历程,文中还考察了分肢钢管间距及隔板厚度对稳定承载力的影响。结果表明,截面刚度变化率决定桅杆的弹性屈曲模态;屈曲模态为＂C＂形的桅杆,弯矩作用导致稳定承载力的降低程度小于屈曲模态为＂S＂形的桅杆;可通过调整分肢钢管间距获得梭形格构柱的最大稳定承载力,相应的分肢间距与＂C＂形、＂S＂形屈曲模态转换的临界分肢间距基本一致;增加隔板厚度对提高＂S＂形屈曲模态桅杆的稳定承载力更为有效。

Stability Behavior of Shuttle-Shaped Steel Lattice Columns With Bending Moment

The stability behavior of shuttle-shaped steel lattice columns subject to combined axial force and bending moment was examined through elastic buckling analysis and geometrically and materially nonlinear analysis.Firstly,the concept of section stiffness variation ratio is proposed for shuttle-shaped lattice columns and the elastic buckling behavior is discussed.Then,the effect of bending moment on the stability behavior of lattice columns is investigated,with the emphasis on the development of axial stress,bending stress and shear stress.The influence of column component spacing and diaphragm thickness on the stability bearing capacity is also analyzed.It is shown that the elastic buckling mode of the lattice column is dependent on its section stiffness variation ratio;for lattice columns with C-shaped buckling mode,the reduction in stability bearing capacity caused by bending moment is smaller than that of columns with S-shaped buckling mode;the maximum stability bearing capacity of the lattice column can be achieved by adjusting the column component spacing,and the spacing corresponding to the maximum capacity is basically consistent with the critical spacing for transformation of C-shaped buckling mode and S-shaped mode;and it is more effective to increase the thickness of columns with S-shaped buckling mode to get larger bearing capacity.