方形钢管混凝土框架二阶效应下极限承载力的高效线弹性迭代分析  

Linear elastic iteration with high efficiency for ultimate bearing capacity of square-profile CFST frame with second order effect

作　　者：杨绿峰[1,2] 赵玉峰[1,2] 解威威 Yang Lufeng;Zhao Yufeng;Xie Weiwei(School of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Engineering Disaster Prevention and Structural Safety of the Ministry of Education,Guangxi University,Nanning 530004,China;Guangxi Road&Bridge Engineering Group Co.,Ltd.,Nanning 530011,China)

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004 [2]广西大学教育部工程防灾与结构安全重点实验室,广西南宁530004 [3]广西路桥工程集团有限公司,广西南宁530011

出　　处：《土木工程学报》2022年第2期1-10,共10页China Civil Engineering Journal

基　　金：国家自然科学基金(51738004)。

摘　　要：传统的弹性模量调整法难以考虑结构二阶效应的影响。为此,该文研究建立了考虑二阶效应影响的方形钢管混凝土(CFST)的齐次广义屈服函数,据此建立了二阶效应下框架结构极限承载力分析的弹性模量缩减法(EMRM)。首先利用二次多项式分别建立了关于套箍系数和稳定系数的影响函数,在此基础上,利用具有分数指数幂的一阶多项式,通过回归分析研究建立了方形CFST压弯构件在二阶效应下的齐次广义屈服函数。其次,通过有策略的缩减高承载单元的弹性模量模拟结构刚度的衰减,进而通过线弹性迭代分析确定方形CFST框架结构的极限承载力,据此分析了二阶效应对不同荷载工况、不同几何参数下的CFST框架极限承载力的影响。最后通过与试验数据和现行增量非线性有限元法对比分析,验证了文章方法具有较强的适用性、较好的计算精度和计算效率。研究结果表明,二阶效应对于CFST中长柱和CFST框架都具有不可忽略的影响。In this work, the elastic modulus reduction method(EMRM) was presented to take into consideration the second order effect on the ultimate bearing capacity of square-profile concrete-filled steel tube(CFST) frames, which is difficult to be dealt with in the conventional elastic modulus adjustment procedures.Firstly, the influence functions for confinement factor and stability factor were developed, respectively, using the quadratic polynomials so that the homogeneous generalized yield function(HGYF) was constructed for the CFST member with second order effect using the first order polynomial with fractional-exponential powers by means of the regression analysis.Secondly, the degradation of structural stiffness was simulated by reducing strategically the elastic modulus of highly-stressed elements, while the ultimate bearing capacity of square-profile CFST frame was evaluated by linear elastic iteration.Finally, it was validated that the proposed elastic modulus reduction method is accurate enough with high computational efficiency for evaluating the ultimate bearing capacity of the square-profile CFST frame with second order effect under in-plane or spatial loadings, when comparing to the results from the incremental nonlinear finite element method and the test data.Results show that the second order effect has significant influences on the medium-long components and the CFST frames.

关 键 词：方形钢管混凝土 二阶效应 承载力 弹性模量缩减法 分数指数幂 齐次广义屈服函数 

分 类 号：TU398[建筑科学—结构工程]