一种能够考虑复杂加载历史的RC框架单元模型

本文提出的单元模型把框架结构构件看作由分布弹塑性梁子单元、节点滑移子单元和剪切子单元等三个在节点上串联的子单元组成。着重介绍了分布塑性梁子单元柔度矩阵的建立过程,该柔度矩阵是在梁端塑性区域平均刚度假定和修正TAKEDA恢复力模型的基础上建立起来的。该单元模型能够考虑非线性变形随复杂加载历史在端部关键受力区域的逐步扩展和反弯点位置的移动,整个推导过程力学概念明确,所获得的柔度矩阵为对称矩阵,便于数值计算。计算结果与试验结果比较表明,本文提出的分布塑性梁单元模型可以较好地反映试件的滞回性能。

An analytical member model for simulating nonlinear response of RC frames

This paper presents an analytical member model for simulating nonlinear static and dynamic response of RC frame, which is able to account for spreading plastic flexure deformation, shear deformation and anchorage slip in the joint. This member model consists of isolating macroscopic member element into three subelements, namely spread plastic beam subelement, joint slip subelement and shear subelement, and thus the stiffness matrix of the frame member element can be easily constructed by calculating the flexibility matrix of each subelement respectively. In this paper, only the flexibility matrix of spread plastic beam subelement is presented in detail, which is constructed based on the assumption of average stiffness along the plastic zone and modified TAKEDA model. This model can take into account the gradual spread of the nonlinear deformation in the key load bearing zone at beam ends along with the complex loading history and the move of the position of contraflexure point. The mechanical concept in the process of derivation is definite and the flexibility matrix obtained is symmetrical. So it is convenient for computation. Comparisons of analytical results with experimental data of RC subassemblies indicate that the proposed model can be used for simulating nonlinear response of RC frames.