组合构件双重非线性分析模型研究与应用

RESEARCH ON THE DOUBLE NONLINEAR ANALYSIS MODEL OF COMPOSITE COMPONENTS

以超高层建筑中当前广泛应用的杆系组合构件为研究对象,采用三维空间梁单元对其进行复杂受力状态下的双重非线性分析。为贴近实际工程同时简化计算,首先根据有限元方法和最小势能原理建立单元考虑几何非线性的弹性切线刚度矩阵;然后通过划分截面广义应变将单元截面刚度矩阵分离为弹性刚度矩阵与塑性刚度矩阵,在假定广义应变增量分布状态基础上,基于纤维模型法推导出单元塑性刚度矩阵;最后将考虑几何非线性的弹性刚度矩阵与塑性刚度矩阵集合成整体刚度矩阵,根据构件自身特性选取合理材料本构关系及数值计算方法进行构件非线性受力分析。数值分析结果表明,该文模型与方法概念清晰、计算精度高,还可应用于钢筋混凝土构件的受力性能非线性分析。

Composite components are widely applied in super high-rise buildings. The double nonlinear behavior of composite components was analyzed by adopting three-dimensional beam element. To match the actual situation and simplify the calculation procedure, elastic tangent stiffness matrix was set up using finite element method according to the principle of minimum potential energy, in which the geometric nonlinearity is also considered; then the element section stiffness matrix was divided into elastic stiffness matrix and plastic stiffness matrix by separating section generalized strain. Subsequently, by assuming the generalized strain increment, the element plastic stiffness matrix was obtained using the fiber model method. Finally, the elastic stiffness matrix, which considers geometric nonlinearity, was combined with the plastic stiffness matrix to obtain the global stiffness matrix. The nonlinear analysis was carried out, showing that the proposed method is reasonably accurate and can be applied to nonlinear analysis of reinforced concrete members.