摘要
本文以空间刚接杆系为计算模型,研究了单层网壳的线性和非线性分枝屈曲分析方法,探讨了一种跳跃失稳的近似分析方法,并编制了计算机程序。 本文提出了“修正相关行列式”的概念,能迅速和准确求解非线性分枝屈曲的第一幅界荷载,并且给出求解相应屈曲模态的方法。本文在采用考虑(?)力影响的精确刚度矩阵的基础上,用直接迭代法,得到相应的荷载位移曲线,并最后得出跳跃失稳或极限荷载近似值。现有算例表明,该方法与大挠度分析方法所得结果接近。
A finite element method for linear and nonlinear bifurcation analysis of single-layer reticulated shells is presented in this paper. An exact stiffness matrix of space beam element considering the effect of axial force is used. For nonlinear bifurcation analysis, a concept of 'modified relative determinant' is proposed, with which it is able to determine the first critical load efficiently and accurately. The method presented in this paper is also able to determine the buckling mode of the structures, which has not been dealt with by previous researches as the authors known. To obtain the loaddeflection curve of the structures, an iterative method is used. And then the snap-through buckling load or ultimated load of the structures can be obtained bythe convergence of iteration. Numerical results are show in good agreement with those obtained by large deflection analysis method.
关键词
网壳
稳定
空间刚架
非线性
Stability, Reticulated shell, Space frame.
