矩形钢管混凝土齐次广义屈服函数与桁架结构极限承载力

研究建立具有广泛适用性的钢管混凝土(CFST)矩形截面的齐次广义屈服函数(HGYF)，据此提出CFST桁架结构极限承载力分析的高效、自适应弹性模量缩减法(EMRM)。首先以约束效应系数为自变量，利用高阶多项式拟合HGYF的待定系数，使之与不同的CFST矩形截面相协调；进而，通过回归分析建立CFST矩形截面的HGYF，并据此建立高承载单元的自适应识别准则。然后，通过自适应缩减高承载单元的弹性模量模拟结构的刚度损伤演化，由此确定CFST桁架结构的极限承载力。通过将CFST构件及结构两个层面的计算结果与模型试验及增量非线性有限元法结果对比分析，验证了该文建立的HGYF和EMRM具有良好的适用性与计算精度，且能够取得更高的计算效率。

Homogenous generalized yield function and ultimate load-bearing capacity analysis of rectangular concrete-filled steel tubular trusses

The homogeneous generalized yield function (HGYF) was developed for the concrete-filled steel tube (CFST) with different rectangular cross sections, and the elastic modulus reduction method (EMRM) was proposed for evaluating the ultimate bearing capacity of the CFST trusses. Firstly, high-order polynomials consistent with different rectangular cross sections were employed to develop the explicit expressions of the undetermined coefficients of HGYF, taking the constraint effect coefficients as arguments, so that the HGYF was developed for CFST components with rectangular sections. Then an adaptive criterion was presented to distinguish the highly-stressed elements. Secondly, the elastic modulus of the highly-stressed elements were reduced to simulate the stiffness damage, then the ultimate bearing capacity was determined for the CFST trusses. The computation results for CFST components and structures by the proposed method agree well with those from the model experiments and the incremental non-linear finite element method, which indicates that the HGYF and the EMRM have good applicability and accuracy with higher efficiency.