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应用红外探测技术跟踪记录了2个纤维增强聚合物复合材料(FRP)加固混凝土试件界面的疲劳损伤发展过程,结合系列疲劳试验分析了界面的疲劳力学性能和疲劳寿命。结果显示FRP-混凝土界面粘结区和剥离区有明显的温度差异,应用红外探测技术可以较准确地检测界面的损伤发展状况。界面的疲劳损伤从跨中位置萌生后向一端扩展,损伤演化可分为萌生、稳定发展和失稳发展3个阶段,稳定发展阶段约占界面疲劳总寿命的99%左右。在界面疲劳寿命的主要阶段内界面的疲劳损伤较小,发展缓慢,FRP应力也变化平稳,表明加固的抗疲劳效果较好。最后给出了界面疲劳寿命的预测方法,界面的疲劳破坏制约了FRP材料强度性能的充分利用。
The development of fatigue damage at the interface of two FRP reinforced concrete specimens was tracked and recorded by using infrared detection technology. The fatigue performance and fatigue life of the interface were analyzed by a series of fatigue tests. The results show that the FRP-concrete interface has obvious temperature difference between the adhesive area and the peeled area. The infrared detection technology can accurately detect the interface damage development. The fatigue damage at the interface expands from one side to the other after midspan initiation. The damage evolution can be divided into three stages of initiation, stable development and instable development. The steady development stage accounts for about 99% of the total fatigue life of the interface. In the main stage of interface fatigue life, the fatigue damage of the interface is small, the development is slow, and the stress of FRP also changes smoothly, which shows that the anti-fatigue effect of reinforcement is better. Finally, the prediction method of the interface fatigue life is given. The fatigue failure of the interface restricts the full utilization of the strength properties of the FRP material.