周芬+冷举良+杜运兴

摘要：在OpenSees平台上采用纤维模型模拟FRP约束混凝土圆柱的受力性能时需要开发相应的本构模型.基于Jiang和Teng提出的分析型骨架本构模型，将不同峰值应力、应变计算公式的计算结果与试验结果进行比较，选择了更为精确的计算公式，并将其引入该骨架模型.该模型还考虑了箍筋对核心混凝土的约束作用，采用FRP极限环向抗拉应变折减系数得出FRP片材在环向受拉破坏时的极限拉应变.根据是否考虑钢筋的疲劳采用两种不同钢筋本构关系对试件进行模拟.采用该模型不但可以得到构件的轴向应力应变关系，还可以计算横向应变与轴向应力的关系，模拟结果与试验结果吻合较好.

关键词：纤维增强塑料;约束混凝土;纤维模型;本构模型

中图分类号：TB83;TM753 文献标识码：A

Research on the Constitutive Models of  FRP

Confined Concrete Cylinder Based on  Fiber Models

ZHOU Fen，LENG Ju-liang， DU Yun-xing

（College of Civil Engineering， Hunan Univ， Changsha， Hunan410082， China）

Abstract：The related constitutive model is needed when using fiber model to simulate the mechanical behavior of FRP confined concrete cylinder on OpenSees platform. Based on the skeleton-line constitutive model proposed by Jiang and Teng， the test results were compared with the calculation results under different peak stresses and strains， and more precise formulas were chosen and taken into the skeleton-line constitutive model. In the constitutive model， with the confinement effect of stirrup on core concrete taken into consideration， the ultimate tensile strain of FRP under hoop tensile failure was obtained by the reduction factors of ultimate hoop tensile strain. In addition， two different constitutive models were adopted to simulate the member according to whether considering the steel fatigue through the constitutive model. Both the relationship of axial stress and strain and the relationship of lateral strain and axial stress for the structural member were obtained， and the prediction results agreed well with the test results.

Key words：FRP（Fiber Reinforced Plastics）;confined concrete;fiber models;constitutive models

OpenSees平台是基于纤维模型的计算平台，与传统的有限元相比，纤维模型能够在保证准确性的基础上大幅降低计算耗时，并且更易收敛，能够用于大型结构的数值模拟.国内学者在该平台上对构件、结构的仿真进行了广泛的研究，并积累了大量的科研成果[1-2].这些研究成果主要集中在钢筋混凝土结构及型钢混凝土结构领域.对于FRP加固的钢筋混凝土结构，OpenSees材料库中缺乏与其对应的本构模型，制约了该平台对这种结构的仿真分析.近年来，由于FRP材料优越的力学性能和物理性能，FRP片材已经广泛地用于加固结构和构件中，特别是震后结构的修复工作，FRP的约束……