电热作用对碳纤维/树脂复合材料界面应力的影响电热作用对碳纤维/树脂复合材料界面应力的影响

碳纤维/树脂复合材料广泛应用于民用航空器结构中，在服役期间会受到复杂环境（湿热、腐蚀、复杂应力和电热作用等）的作用，低强度电流对碳纤维/树脂复合材料的影响受到的关注较少。以碳纤维/树脂复合材料为研究对象，根据碳纤维的温敏效应和通电时的电阻变化规律，计算出碳纤维单丝/环氧树脂复合试样的界面温度范围，之后采用拉曼光谱测试和单丝断裂实验研究了低强度电流对单丝复合体系界面应力和界面剪切强度的影响。结果表明:随着电流强度的提高，单丝复合体系的界面温度随之升高，电流为8 mA时，界面温度高达约200℃。随着电流强度的增大，单丝复合体系的界面压缩应力表现为先增大后减小的趋势，电流高于7 mA后，界面处树脂出现烧蚀降解破坏；单丝断裂实验结果表明随着电流强度增大，单丝复合体系的界面剪切强度呈现先升后降的趋势，在6 mA时界面剪切强度达到最大值62.39 MPa，而8 mA时界面剪切强度仅为34.95 MPa。 

Influence of electro-thermal effect on interfacial stress of carbon fiber reinforced polymer composites

Carbon fiber reinforced polymer composites were widely used in civil aircraft structures and subjected to complex environments (hydrothermal, corrosion, complex stress, and electro-thermal effects, etc.) during service. But the impact of low-intensity currents on carbon fiber reinforced polymer composites has attracted less attention. In this paper, the carbon fiber/resin composites were taken as the research object. The interface temperature range of the carbon fiber monofilament/epoxy resin composite specimen was calculated based on thermo sensitivity of carbon fibers and the dynamic of resistance change when an electric current was applied. Raman spectroscopy test and monofilament fracture test were used to study the influence of low-intensity current on the interfacial stress and interfacial shear strength of monofilament composite system. The results of the study show that:with increment of the current intensity, the interface temperature of the monofilament composite system is increasing. When the current is up to 8 mA, the interface temperature is as high as about 200℃.With the increase of the current intensity, the interfacial compressive stress of the monofilament composite system increases first and then reduces. When the current is higher than 7 mA, the resin at the interface undergoes ablation degradation and destruction. Monofilament fracture experiment illustrates that with the increase of the current intensity, the interfacial shear strength of the monofilament composite system increases initially and then decreases. The interfacial shear strength reaches a maximum of 62.39 MPa at 6 mA and the interface shear strength is only 34.95 MPa at 8 mA.