建筑结构动力分析有限元模型

The finite element model for dynamic analysis of building structures

为了正确处理结构—地基动力相互作用 ,改善以往固定边界模型将地震能量全部陷入结构计算模型的不合理状况 ,以框架结构为例提出了建筑结构地震反应分析的有限元模型及其透射边界。模型中采用四结点平面应力等参单元模拟上部框架结构的梁柱构件。地基采用平面应变四结点等参单元离散 ,在地基有限元网格中设置底部透射边界和侧面捆绑边界以考虑结构—地基的动力相互作用。算例表明上述建筑结构地震反应分析的有限元模型给出了合理的结构地震反应 ,可进一步应用于地震时结构几何与材料非线性响应直至结构破坏时的计算机仿真。

In order to take the dynamic interaction of structure and foundation into full account and overcome the drawback of classical fixed boundary models which trap all earthquake energy into the computation models, a finite element model with transmitting boundaries has been proposed for the earthquake response analysis of building structures. In the model, components of upper frame structures, such as beams and columns, are discretized with plane-stress 4-node quadrilateral parametric elements, and foundations with plane-strain 4-node quadrilateral parametric elements. The lateral boundary nodes of the foundation finite element mesh are tied together and the bottom of the mesh is imposed with viscous dampers so that the dynamic interaction between structures and foundations can be fully taken into consideration. Numerical examples presented in the paper have shown that the finite element model correctly represents the earthquake responses of the structures considered. The model can be further extended for the computer simulation of both geometric and material nonlinear earthquake responses of building structure.