硫酸盐干湿循环作用下CFRP-黏土砖界面粘结性能退化规律分析

碳纤维增强复合材料(CFRP)与黏土砖界面的粘结性能是外贴CFRP加固技术的关键,为了解CFRP-黏土砖界面粘结性能在硫酸盐侵蚀下的退化规律,对硫酸盐干湿循环不同周期下的加固试件进行了单面剪切试验,结果表明:硫酸盐侵蚀对CFRP片材与浸渍胶性能影响并不明显,但对CFRP-黏土砖界面粘结性能影响较大,CFRP-黏土砖界面剪应力、承载力均随循环次数呈先小幅上升后明显下降的趋势;在试验基础上,根据已有的理论,提出硫酸盐干湿循环作用下CFRP-黏土砖界面粘结-滑移模型,通过与试验值对比分析发现,模型能够很好地反映CFRP-黏土砖界面的粘结性能退化规律。基于ABAQUS软件,利用内聚力本构关系模型对界面力学行为进行数值模拟,结果表明,内聚力模型可以很好地模拟界面的非线性力学行为,数值模拟值与试验值吻合较好。

Degradation Law of CFRP-Clay Brick Interface Bond Property under Sulfate Drying and Wetting Cycles

The bond property of the interface between carbon fiber reinforced polymer (CFRP) and clay brick is the key of external CFRP reinforcement technology. In order to understand the degradation law of the bond property of the CFRP-clay brick interface under sulfate erosion, a single shear test was carried out on the specimens strengthened under different sulfate drying and wetting cycles. The results show that the influence of sulfate erosion on the properties of CFRP sheet and impregnating glue is not obvious, but it has a great influence on the bond properties of CFRP-clay brick interface. The shear stress and bearing capacity of the CFRP-clay brick interface increase slightly first and then decrease obviously with the increase of drying and wetting cycles. On the basis of the experiment and the existing theory, the bond slip model of the CFRP-clay brick interface under the action of sulfate drying and wetting cycles is proposed. The model can well reflect the bond property degradation law of the CFRP-clay brick interface by comparing with the experimental value. Based on ABAQUS software, the cohesive force constitutive model was used to simulate the mechanical behavior of the interface. The results show that the cohesive force model can well simulate the nonlinear mechanical behavior of the interface, and the numerical simulation values are in good agreement with the experimental values.