基于纤维模型的FRP约束混凝土圆柱本构模型研究

Research on the Constitutive Models of FRP Confined Concrete Cylinder Based on Fiber Models

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.

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.