基于碳纳米纸传感器的复合材料结构低速冲击损伤监测

Monitoring of Low-velocity Impact Damage in Composite Structures Based on Carbon Nanotubes’ Buckypaper Sensors

针对复合材料对冲击载荷比较敏感、内部损伤不易发现的问题,提出一种利用碳纳米纸薄膜作应变传感器的复合材料结构件低速冲击损伤监测方法。在拉伸条件下,对圆形和矩形碳纳米纸薄膜进行不同方向的传感系数测试,发现圆形碳纳米纸传感器具有较高且稳定的传感系数155.63,可以作为全向传感器监测冲击损伤。复合材料结构的冲击损伤由传感器的电阻变化率和超声C扫描结果同步表征。研究结果表明,传感器的电阻随着冲击能量的增加而增加,基于全向碳纳米纸传感器的结构健康监测不仅可以灵敏感知低速冲击损伤,为损伤程度评估提供客观数据,而且通过分析不同方向BP传感器的电阻变化可以判断损伤位置。进一步与传统C扫描结果相比较表明,全向碳纳米纸传感器可以有效预判低速冲击损伤,用于航空航天复合材料结构件的实时在线健康监测。

A monitoring method for low-velocity impact damage in composite structures based on carbon nanotubes’ Buckypapers(BP) as strain sensor was proposed in this paper. The sensing coefficients of circular and rectangular BP in different tensile directions were measured. The results showed that the circular BP sensor had a steady sensing coefficient of 155.63 which could serve as an omnidirectional sensor to monitor the impact damage. The resistance change ratio of omnidirectional BP sensors and the results of C scanning were synchronous characterization of the low-velocity impact damage of the composite structures. The experiment results showed that the electrical resistance of omnidirectional BP sensors increased with increase of the impact loading. The structure monitoring based on omnidirectional BP sensor was sensitive to impact damage and could provide objective data for the evaluation of the damage in composite structures. In addition, the location of damage could be determined by analyzing the resistance changes of BP sensor in different directions. Comparing with the results of traditional C-scan, the omnidirectional CNTs Buckypaper sensor could efficiently predict the low-velocity impact damage and may be applied in real time health monitoring of composite structures in spacecraft.