圆钢管混凝土结构非线性有限元分析

Nonlinear finite element analysis of concrete filled circular steel tubular structures

基于合理的钢管混凝土拉、压材料数值本构模型,采用U.L.列式单元增量平衡方程,引入分层梁单元材料非线性分析理论,通过调整截面形心应变和曲率,使梁端内外力平衡,完善了分层单元法,编制了相应的非线性有限元程序,并对已有钢管混凝土结构面内受力,如钢管混凝土偏压柱、不等端弯矩钢管混凝土偏压柱、钢管混凝土压弯构件和钢管混凝土模型拱肋等试验资料进行双重非线性有限元分析。结果表明:几组钢管混凝土模型拱和钢管混凝土压弯构件的荷载-变形曲线和极限承载力与试验结果最接近,验证了本文方法与程序的可靠性,通过与其他学者计算结果相比,表明本文方法具有较高的计算精度。

Based on the appropriate numerical constitutive model and U.L. formula of element incremental equilibrium, layered finite element method is adopted for dealing with geometrical as well as material nonlinearities of concrete filled steel tubular （CFST） structures subjected to in-plane load. Through adjusting the strain at centroid of cross section and the curvature, the external nodal loads is in equilibrium with the internal stress, thus the layered finite element method is perfected and a FORTRAN program is developed. The reliability of the present method and program was validated by comparing with the test results of CFST structures subjected to in-plane load such as CFST columns under eccentric loading of equal end-moment or unequal end-moment, CFST beam-columns, and CFST arches from literature. The present method is more accurate comparing with other existing analytical methods.