FRP管-混凝土-钢管复合套管约束性能有限元分析

为了研究FRP管-混凝土-钢管复合套管的约束性能,采用修正的Hognestad表达式来描述混凝土单轴受压应力-应变关系,利用ABAQUS软件对FRP约束混凝土短柱轴压试验进行有限元模拟,并与试验结果进行了比较,表明有限元模型通过精确定义材料参数、单元模型、表面作用、边界条件,可准确描述FRP约束混凝土短柱力学性能.在此基础之上,分析了FRP管-混凝土-钢管复合套管中3种材料厚度变化对管约束性能的影响.结果表明,在复合套管的约束作用下,核心混凝土的轴向应力-应变曲线呈现双线性的特点,复合管中的钢管主要影响第一线性段,而FRP管和混凝土主要影响第二线性段.该结论为今后进行该类组合柱的研究提供了参考.

Finite element analysis for confinement behavior of hybrid FRP tube-concrete-steel tube composite bushing

In order to study the confinement behavior of hybrid FRP tube-concrete-steel tube composite bushing, a finite element(FE) method is introduced to simulate FRP confined concrete short columns using ABAQUS software, and a modified Hognestad formula is presented to describe the stress-strain relations of concrete under uniaxial compression. The comparison of simulation and test results shows that this FE method does well in predicting mechanic properties of FRP confined concrete short columns by defining material parameters, element models, surface interactions and boundary conditions accurately. Based on these analytical data mentioned above, confinement behavior of FRP tube-concrete-steel tube composite bushing under three kinds of material thicknesses is analyzed. Study results indicate that the stress-strain curve of the concrete confined by the composite bushing presents a bilinear shape, in which the first line is decided by the steel tube mainly, while the second one by the FRP tube and concrete. Some references are provided for further research of this kind of composite column.