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提出一种具有局部搭接结构的树脂基碳纤维智能层,将其敷设于结构表面以检测结构受载时的变形,实现对结构大范围监测。基于该智能层,采用单轴拉伸和三点弯曲的加载方式,对构件进行应变和位移检测。实验发现,碳纤维局部搭接结构是引起力阻效应的主要因素,其单位应变的电阻率变化的灵敏度达到104,相当于非搭接连续碳纤维复合材料力阻效应灵敏度的34倍。实验结果还进一步表明,树脂基搭接碳纤维智能层力阻曲线光滑稳定,其传感极限约为8500με。建立了树脂基搭接碳纤维复合材料的电学模型,揭示了这种力阻效应主要来源于搭接界面处层间电阻的变化,并从纤维轴向力、搭接面积和层间剪应变三个方面解释了这种层间电阻变化的机制。
A resin-based carbon fiber smart layer with a local overlap structure is proposed, which is laid on the surface of the structure to detect the deformation of the structure under load, so as to monitor the structure in a wide range. Based on the smart layer, the uniaxial tension and the three-point bending method are adopted to detect the strain and displacement of the component. The experimental results show that the partial lap structure of carbon fiber is the main factor that causes the resistance effect. The sensitivity of resistivity change per unit strain reaches 104, which is equivalent to 34 times the resistance sensitivity of non-lapped continuous carbon fiber composite material. The experimental results further show that the resistance curve of resin-bonded carbon fiber smart layer is smooth and stable, and its sensing limit is about 8500με. The electrical model of resin-based lapped carbon fiber composites was established. The force resistance effect was mainly attributed to the change of interlaminar resistance at the lap interface. From the three aspects of fiber axial force, lap area and interlaminar shear strain This explains the mechanism of this change in interlayer resistance.