基于应力诱导巨磁阻抗效应的飞机复合材料结构健康监测关键问题研究

Build-in sensing technique is one of the important technologies in structural health monitoring of composites. In this project, aiming at the key issues of structural health monitoring of composites used in airplane based on stress-induced giant magneto-impedance effect, we firstly fabricate the Co-based amorphous soft magnetic microfibers and optimize its properties, then investigate the regulation mechanism of giant magneto-impedance in microfibers under stress. The compositions and regulating process will be optimized based on the analysis of magnetic domain structure, and theoretical model of stress-induced impedance will be proposed. Finally, we will carry out the design, fabrication and testing of build-in stress sensor in fiber-reinforced composites. According to the investigation of this project, we will reveal the physical nature of the effect of stress on magnetic domain structure and giant magneto-impedance, clarify the mechanism of action between composition, magnetic domain structure and giant magneto-impedance, and realize the accurate monitoring of damages in fiber-reinforced composites. The above proposed project will provide theoretical and experimental basis for the optimization of electromagnetic properties of Co-based amorphous microfibers and developing new high-performance stress-sensitive materials. At the same time, it will lay the foundation of the application of current structural health monitoring technology in the field of civil aviation.

嵌入式传感技术是复合材料结构健康监测的重要技术手段。项目针对应力诱导巨磁阻抗效应在飞机纤维增强复合材料结构健康监测领域应用所面临的问题，从高性能钴基非晶软磁合金微米纤维的制备和性能优化出发，研究应力作用下钴基非晶软磁纤维巨磁阻抗效应的调控机制，优化合金成分和调制处理工艺，并建立应力阻抗理论模型，最终开展纤维增强复合材料嵌入式应力传感器的设计、制备与测试研究。通过研究，将揭示应力对巨磁阻抗性能影响的物理本质，阐明合金成分和微观磁畴结构对微米纤维应力诱导巨磁阻抗性能的内在作用机制，建立基于巨磁阻抗信号检测的局部损伤状态评价模型，实现对纤维增强复合材料局部应力/微裂纹的准确监测。为进一步优化钴基非晶软磁合金微米纤维的电磁性能、完善和发展新型高性能应力传感器提供理论和实验依据，并为实现基于应力诱导巨磁阻抗效应的复合材料结构健康监测技术在民航领域的应用奠定基础，具有重要的科学意义和工程技术价值。

项目针对应力诱导巨磁阻抗效应在飞机纤维增强复合材料结构健康监测领域应用所面临的问题，从高性能钴基非晶软磁合金微米纤维的制备和性能优化出发，研究应力作用下钴基非晶软磁纤维巨磁阻抗效应的调控机制，优化合金成分和调制处理工艺，最终开展基于应力诱导巨磁阻抗效应的纤维增强复合材料中微观裂纹缺陷的检测研究。具体研究了Ni、Cr、P元素以及去应力退火、焦耳退火、焦耳应力退火和磁场退火处理对CoFeSiB系非晶合金纤维的巨磁阻抗效应和应力诱导阻抗效应的影响行为，结果表明电流退火和横向磁场退火对钴基非晶薄带的GMI、GSI效应提升较为明显；适量的P掺杂、Nb掺杂可以提高薄带GMI、GSI效应，具体体现在经磁场退火的Co69Fe5.5Ni1Si13.5P1B10样品的最大巨磁阻抗比为100.8%、GSI比34.3%，经磁场退火的Co68Fe4.5Si12.5B10Nb1Ni3样品的最大巨磁阻抗比为130.4%、GSI比42.7%，经磁场退火的薄带性能均明显好于经去应力退火的薄带。最后，采用巨磁阻抗GMI传感器搭建了玻璃纤维增强环氧树脂复合材料内部裂纹缺陷检测系统，对玻璃纤维增强环氧树脂复合内部直径大小为50～175μm的裂纹缺陷进行了检测。GMI传感器核心元件采用厚度30μm、宽度1mm的Co68Fe4.5Si12.5B10Nb1Ni3非晶薄带，以非线性非对角模式工作。结果表明，传感器可以检测出直径大于50μm的裂纹缺陷，根据测量信号的标定可以分析出裂纹缺陷所在的位置和大小。