水性环氧树脂基石墨烯传感元件对混凝土应变的感应特性

Sensing characteristics of waterborne epoxy resin based graphene sensor to concrete strain

  • 摘要: 为推动导电纳米复合材料在混凝土变形监测中的应用,采用溶液共混法制备了水性环氧树脂基石墨烯传感元件。首先,研究了石墨烯质量分数对传感元件灵敏度、线性度、重复性和耐疲劳性等工作性能的影响;然后,分析了影响传感元件对混凝土应变感应特性的关键因素,通过混凝土压缩试验,研究了单调和循环压缩下传感元件对混凝土应变的电阻响应规律,建立了传感元件电阻变化率与混凝土压应变的关系。结果表明:当石墨烯质量分数为0.4%~0.8%时,传感元件具有较高的灵敏度系数、良好的线性度和重复性;当石墨烯质量分数为0.6%时,传感元件的耐疲劳性能最优;混凝土泊松比对传感元件的应变感应灵敏系数影响较大,灵敏系数随泊松比增大而减小;传感元件能够有效感应循环荷载下混凝土的应变,表现出良好的重复性和稳定性,可用于混凝土结构的疲劳监测。

     

    Abstract: To promote the application of conductive nanocomposites in concrete deformation monitoring, the waterborne epoxy resin based graphene sensor was prepared by solution blending method. Firstly, the influence of graphene mass fraction on the sensitivity, linearity, repeatability and fatigue resistance of the sensor was studied. Then, the key factors affecting the strain sensing characteristics of the sensor on concrete was analyzed. Through concrete compression tests, the resistance response of the sensors to concrete strain under monotonic and cyclic compression was studied, and the relationship between the resistance change rate of the sensor and concrete compressive strain was established. The results showed that, when the graphene mass fraction was between 0.4% ~ 0.8%, the sensor had a high sensitivity coefficient, good linearity and repeatability. When the graphene mass fraction was 0.6%, the fatigue resistance of the sensor was optimal. The Poisson's ratio of concrete had a significant impact on the strain sensing sensitivity coefficient of the sensor. The sensitivity coefficient decreased as the Poisson's ratio increased. The sensor could effectively sense the strain of concrete under cyclic loads, exhibiting good repeatability and stability, and could be used for fatigue monitoring of concrete structures.

     

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