一种考虑初始缺陷影响的非线性梁单元

在目前广泛应用的梁单元中，尚缺乏全面考虑以下四种因素影响的粱单元：(1)轴力的影响；(2)剪切交形的影响；(3)初始弯曲的影响；(4)弯曲变形对轴向应变的影响，即弓形效应。事实上，以上四种非线性因素都会对钢框架结构的稳定和极限承载力有影响，需同时考虑。本文将致力于推导同时考虑以上四种因素影响的平面梁单元的平衡微分方程，最后得到精确的粱单元刚度矩阵，并研究以上四种因素对钢框架构件及钢框架结构的影响。

A nonlinear beam element considering initial imperfection

Among all the beam elements currently used, such a beam element that can consider all the four nonlinear factors listed below is insufficient: (1) axial force factor, (2) shear deformation factor, (3) original curve factor, (4) the effect of flexural deformation on axial strain, namely bowing effect. In fact, all the four nonlinear factors may all affect the stability or ultimate load-bearing capacity of steel frames seriously , thus they can not be ignored and should to be considered simultaneously instead. In this paper, the equilibrium differential equation of beam element considering all the four nonlinear factors is derived and the precise beam element stiffness matrix is obtained, through the stiffness matrix we can evaluate the influence of all these four factors on members or the whole structure of steel frames.