传统纤维模型的一些新发展

纤维模型是结构体系模拟技术发展中的重要里程碑，它具有简单、高效、通用的特点，近年来得到了广泛应用，但其基本假定决定了其在许多结构体系关键效应的模拟方面存在显著缺陷。该文综述了研究团队近7年来针对若干体系计算的关键难点对传统纤维模型进行的大量改进和发展工作。首先在通用有限元程序MSC.MARC平台上开发完成了传统纤维模型并将其拓展至组合框架结构的模拟。随后针对四个体系模拟的关键难点，包括组合框架的楼板空间组合作用、核心筒连梁的非线性剪切和滑移效应、构件端部锚固纵筋滑移效应和钢筋混凝土梁柱构件开裂全过程行为，在对机理和规律充分研究的基础上，分别提出了考虑楼板空间组合作用的纤维模型、考虑剪切和滑移非线性的连梁纤维模型、考虑端部锚固纵筋滑移效应的纤维模型和裂缝宽度全过程定量预测的纤维模型等四个新型纤维模型。这些模型既保持了传统纤维模型的优点，同时能够较准确地考虑上述复杂效应，模拟结果得到了大量试验数据和精细有限元的充分验证。基于上述成果，团队同时开发了一套涵盖钢筋混凝土结构、钢结构以及组合结构等工程常用结构形式的非线性分析程序COMPONA-MARC，为结构体系的精细化模拟提供了强大的平台和工具。

SOME ADVANCES IN CONVENTIONAL FIBER BEAM-COLUMN MODEL

The fiber beam-column model, which is an important milestone in the development of simulation technique for structural systems, has been widely used in recent years with its simplicity, efficiency and generality. However, the poor simulation results in many key issues of the structural system using the model cannot be avoided due to the limitation of the basic assumptions of the model. This paper thoroughly reviews the research group's 7-years' efforts and progress in improving the conventional fiber beam-column model to solve several critical problems in structural simulation. Firstly the conventional fiber beam-column model is developed on the platform of general finite element software MSC.Marc and further expanded to the simulation of steel-concrete composite frames. Then four new fiber beam-column models are proposed to give satisfactory prediction results to four key issues in structural simulation including the slab spatial composite effects in composite frames, the nonlinear shear and sliding effects of coupling beams, the rebar anchorage slip in the footings and the whole-process cracking behavior of RC beam and columns, respectively. These models are proved to completely keep the advantages of conventional fiber beam-column models and accurately consider the above complicated effects, according to the verifications by numerous test data and elaborate finite element analysis. Based on the proposed models, a nonlinear analysis program COMPONA-MARC is developed for commonly used structural systems such as RC, steel and steel-composite structures, which provides a powerful platform and tool for elaborate nonlinear structural simulations.