纤维杆元模型在框架结构非线性分析中的应用

Application of Fiber Line Element Model in Nonlinear Analysis of Frame Structures

本文基于Fiber模型,结合分段变刚度概念,推导建立了便于框架结构非线性分析应用的纤维杆元模型,即由杆件两端弹塑性区的纤维子单元及杆件中部弹性区的弹性子单元组成。弹塑性区由于受力较大,采用精细的纤维子单元模拟,中间弹性区受力相对较小,直接采用弹性子单元代替;同时,应用增分理论,分别推导了三维纤维子单元及弹性子单元的单刚矩阵,并采用静力凝聚方法,集成了三维纤维杆元模型的刚度矩阵。另外,直接应用混凝土及钢筋的本构关系,利用该计算模型对一栋12层框架结构进行了时程非线性分析,计算结果与振动台试验结果进行了比较,比较结果表明两者在结构动力特性,位移响应方面等均吻合较好,验证了该模型的有效性,可为推广使用提供参考。

Based on the idea of fiber model, a fiber line element model was provided, which was mainly comprised of fiber element in the elasto-plastic region because of large stress, and the elastic element in the elastic region was used for its small stress. Furthermore, the stiffness of fiber element and elastic element were built up, and the stiffness matrix of fiber line element model was also derived. Moreover, the dynamic response of a 12 floor frame structure, using the fiber line element, was computed and compared to the shaking table test of same model structure. The good agreement between them indicates that the fiber line element model proposed here is reasonable and efficient in the nonlinear analysis of frame structure buildings.