基于有限元法的抛物线拱结构弹塑性稳定性分析

摘要

应用大挠度弹塑性有限元法对承受径向均布荷载和跨中集中荷载的抛物线拱平面内及平面外稳定承载力进行研究.使用弧长法对拱结构平面内屈曲荷载—位移平衡路线及平面外屈曲荷载—位移平衡路线进行全过程跟踪研究.分析抛物线拱结构在不同矢跨比和支承条件下发生弹塑性屈曲的规律,分析中考虑了材料非线性和初始几何缺陷等因素的影响.对相同截面不同矢跨比抛物线拱的平面内二次分叉屈曲荷载、平面外二次分叉屈曲荷载和平面内极限点屈曲荷载进行对比研究,其结果为抛物线拱结构失稳问题的研究提供了依据.%h presents the study on in-plane and out-plane stability capacity of parabolic arch subjected to radial uniform load and concentrated load by employing an elastic plastic large displacement finite element analysis.The full in-plane buckling load-displacement equilibrium paths and out-of-plane buckling load-displacement equilibrium path is theoretically investigated by using finite element approach in conjunction with the arc-length method.The law of elastic-plastic buckling of parabolic arch structure is analyzed under different rise-span ratios and supporting conditions,considering the influence of various factors,such as material nonlinearity and initial geometric imperfection.The comparative studies of in-plane secondary bifurcation buckling load,out-of-plane secondary bifurcation buckling load and in-plane primary buckling load of parabolic arch with some sections and different rise-span ratios are carried out,and the result provides basis for the study of the structural instability problems.