扰动法在结构分枝失稳分析中的应用

对结构进行平衡路径的跟踪分析，是全面了解该结构的受力性能所必须进行的一项工作。目前的结构非线性稳定分析技术一般仅对极值点失稳型问题较为有效，而对分枝点失稳型问题则困难较多。对于具有缺陷敏感性的结构，如拱结构、壳体等，在普通荷载作用下，其失稳路径常包含分枝点。文献1]提出并认为位移扰动法和力扰动法在分析结构分枝失稳时具有很好的效果。本文采用多个不同类型的算例，对扰动法在结构分枝失稳问题中的应用进行了分析比较，表明该方法具有较强的跟踪能力。最后，就扰动法在结构分枝失稳问题中的应用提出几点建议。

Application of Perturbation Methods in Bifurcation Instability Problem

It is very necessary and important to trace the complete load-deflection paths in order to know comprehensively the characteristics of structures subjected to loads. Unfortunately, the achieved nonlinear stability analysis techniques are workable to trace the equilibrium paths only including extreme points. But to the bifurcation paths, most of them can not lead to satisfactory results, particularly to the large-scale structures with sensitivity of initial imperfections such as arch structures, shell, etc. . In author's another paper, the displacement perturbation method and the force perturbation method were presented and proved to be the efficient methods to trace the bifurcation paths. In this paper, the stability of several examples and a large-scale single-layer reticulated shell is analyzed. Finally, some conclusions about using the perturbation method in instability with bifurcation points are drawn.