任意截面预应力混凝土细长柱的非线性分析

提出了轴力和双向弯曲作用下任意截面混凝土和预应力混凝土细长柱的非线性有限元计算模型。分析时既考虑了由单元变形和轴力二次矩引起的几何非线性效应,也考虑了由材料非线性应力应变关系和截面刚度矩阵引起的材料非线性效应。推导了非线性全过程分析的标准有限元公式,得到的单元刚度矩阵可分割成三个子矩阵,分别反映了材料非线性、材料非线性和单元大位移的耦合、轴力二次矩等三种不同的非线性作用效应。计算分析结果和试验结果吻合较好。

NONLINEAR ANALYSIS OF PRESTRESSED CONCRETE SLENDER COLUMNS WITH ARBITRARY CROSS-SECTION

A nonlinear finite element computational model for reinforced and prestressed concrete slender columns with arbitrary cross-section under axial load and biaxial bending is presented. The effects of both geometrical nonlinearity and material nonlinearity are considered. In this paper, geometrical nonlinearity is caused by element deformation and secondary moment of axial force, and material nonlinearity is caused by nonlinear stress-strain relations of materials and section stiffness matrix. The standard finite element formulae for nonlinear complete analysis are derived. The acquired element stiffness matrix can be partitioned into three submatrices reflecting three different nonlinear effects: material nonlinearity, coupling of material nonlinearity and large element displacement, and secondary moment of axial force, respectively. The results agree well with the experimental ones.