嵌入三维编织复合材料的碳纳米线应变传感特性

为实现三维编织复合材料的原位结构健康监测，研制了嵌入碳纳米线的三维五向编织复合材料预制件，建立了基于三维编织复合材料试件的碳纳米线应变传感实验系统，分析了嵌入三维编织复合材料中的碳纳米线应变传感特性。结果表明：在单调拉伸和循环加载卸载过程中，嵌入三维编织复合材料的碳纳米线传感器电阻变化与试件应变的线性相关性较高；在较大载荷循环加载卸载后，碳纳米线传感器产生的残余电阻可用于检测试件的损伤或累积损伤；引入电阻应变相关系数建立了电阻变化净差值与机械应变净差值的应变传感方程，可实现基于碳纳米线传感器的三维编织复合材料原位结构健康监测。

Strain sensing characteristics of carbon nanoyarns embedded in three-dimensional braided composites

In order to realize in-situ structural health monitoring of 3-D braided composites,3-D five-directional braided composite preforms embedded with carbon nanoyarns were prepared, a carbon nanoyarn strain sensing experimental system based on 3-D braided composite specimens were established, and the strain sensing characteristics of carbon nanoyarns embedded in 3-D braided composites were analyzed.The results show that during the process of monotonic stretching and cyclic loading and unloading, the resistance change rate of carbon nanoyarn sensors embedded in 3-D braided composites and the strain of specimens maintain a good linear correlation. After cyclic loading and unloading under heavy load, the residual resistance generated by the carbon nanoyarn sensors can be used to detect the damage or cumulative damage of specimens.The strain sensing equation for the net difference of resistance change and the net difference of mechanical strain established after introducing the coefficient of correlation of resistance to strain could achieve in-situstructural health monitoring of 3-D braided composites.