Abstract The concrete-filled FRP (Fiber-reinforced Polymer)-steel composite tube (CFCT) column is a new structure that integrates the advantages of various materials. The establishment of the cyclic stress-strain relationship under axial loading is of great importance for the seismic analysis and design method of this new structure. In this study, the stress-strain behaviors of six CFCT columns with various FRP thicknesses and types under cyclic axial loading were investigated. The experimental results reveal that the failure process is homologous to that of the CFCT column under monotonic axial compression. CFCT columns that are confined by carbon FRP (CFRP) can achieve higher strength and deformation capacity. The ratio of the plastic strain to the unloading strain enhances with the number of loading cycles. When the axial strain develops to 0.02, the ratio tends to be close to 1.0, and the plastic strain becomes difficult to recover. CFRP plays a more important role in inhibiting the development of plastic deformation compared with basalt FRP (BFRP). On the basis of experimental results, a complete design-oriented stress-strain model is established to predict the cyclic stress-strain relationship of CFCT columns for the first time, and this model includes equations for predicting the returning strain, the plastic strain and the unloading and reloading loading paths. The proposed model can predict the main features of the cyclic stress-strain behaviors of CFCT columns accurately and conveniently both before and after FRP fracture.

中文翻译：

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FRP-钢复合管柱在循环轴压作用下的解析模型

摘要 FRP（纤维增强聚合物）-钢复合管（CFCT）柱是一种综合多种材料优点的新型结构。轴向载荷作用下循环应力应变关系的建立对于这种新型结构的抗震分析和设计方法具有重要意义。在这项研究中，研究了具有不同 FRP 厚度和类型的六个 CFCT 柱在循环轴向载荷下的应力应变行为。实验结果表明，在单调轴压作用下，CFCT柱的破坏过程与CFCT柱的破坏过程相似。由碳纤维 FRP (CFRP) 约束的 CFCT 柱可以实现更高的强度和变形能力。塑性应变与卸载应变之比随着加载循环次数的增加而增加。当轴向应变发展到 0 时。02，比值趋于接近1.0，塑性应变变得难以恢复。与玄武岩玻璃钢（BFRP）相比，碳纤维复合材料在抑制塑性变形发展方面起着更重要的作用。在实验结果的基础上，首次建立了完整的面向设计的应力-应变模型，预测了CFCT柱的循环应力-应变关系，该模型包括预测返回应变、塑性应变和应力应变的方程。卸载和重新加载加载路径。该模型可以准确、方便地预测FRP断裂前后CFCT柱的循环应力应变行为的主要特征。与玄武岩玻璃钢（BFRP）相比，碳纤维复合材料在抑制塑性变形发展方面起着更重要的作用。在实验结果的基础上，首次建立了完整的面向设计的应力-应变模型，预测了CFCT柱的循环应力-应变关系，该模型包括预测返回应变、塑性应变和应力应变的方程。卸载和重新加载加载路径。该模型可以准确、方便地预测FRP断裂前后CFCT柱的循环应力应变行为的主要特征。与玄武岩玻璃钢（BFRP）相比，碳纤维复合材料在抑制塑性变形发展方面起着更重要的作用。在实验结果的基础上，首次建立了完整的面向设计的应力-应变模型，预测了CFCT柱的循环应力-应变关系，该模型包括预测返回应变、塑性应变和应力应变的方程。卸载和重新加载加载路径。该模型可以准确、方便地预测FRP断裂前后CFCT柱的循环应力应变行为的主要特征。该模型包括用于预测返回应变、塑性应变以及卸载和重新加载加载路径的方程。该模型可以准确、方便地预测FRP断裂前后CFCT柱的循环应力应变行为的主要特征。该模型包括用于预测返回应变、塑性应变以及卸载和重新加载加载路径的方程。该模型可以准确、方便地预测FRP断裂前后CFCT柱的循环应力应变行为的主要特征。