结构弹塑性分支屈曲分析的近似方法

仿照压杆弹塑性分支屈曲分析的切线模量理论，把已进入塑性的的元的弹性模量 用相应的切线模量取代，从而将组合结构的弹塑性分支屈曲问题转化为变刚度组合结 构的弹性屈曲分析。给定材料的弹塑性物理关系．对进入塑性的单元，用０．６１８法搜 寻切线模量，通过数次迭代，即可求得弹塑性分支屈曲的临界载荷和相应的屈曲波 形。

An Approximate Method for Elasto-Plastic Buckling Analysis of the Structrues

In this paper, an approximate algorithm is presented for elasto-plastic buc- kling analysis of the structures by means of FEM. In imitation of the tangent modulus theory for the elasto-plastic buckling of bars, the elastic modulus of the plastic elements entered in the pre-buckling is replaced with its tangent modulus and then the elasto-plastic buckling analysis of structures is transformed into the elastic buckling one of the variable stiffness structures. Once the elasto-plastic relationship of material is given, the tangent modulus of plastic elements in the pre-buckling can be searched by golden section method and the critical load and the relevant buckling mode will be interatively computed. Some numerical exa mples are given to demomstrate that the algorithm presented is effective.