针对飞机金属螺栓连接结构中螺栓孔孔边裂纹定量监测需求,提出了一种基于花萼状涡流传感器的损伤监测智能垫片,构建智能垫片监测半解析模型,分析垫片材料电磁属性对损伤监测效果的影响,并进行在线监测试验验证分析结果.半解析模型结果表明,智能垫片各个感应通道的幅值比变化量随垫片磁导率增大而增大,而随垫片电导率增大而减小.程序载荷谱作用下2A12-T4铝合金试件疲劳裂纹监测试验结果表明,铝合金和不锈钢材料的支撑垫片均能有效实现裂纹损伤的定量监测,但不锈钢材料的智能垫片其监测曲线比铝合金材料的智能垫片平滑,监测效果好.将各通道幅值比变化曲线中的拐点作为特征点,通道1能够对累积损伤进行监测,通道2,3,4能够对疲劳裂纹扩展长度进行定量监测,监测精度达到1mm.
To meet the need of monitoring the crack damage located at bolt hole of metallic boltedjoint structure,a kind of damage monitoring smart washer with rosette eddy current sensor was proposed.The influences of washer electromagnetic properties on monitoring capability were analyzed based on constructed semi-analytic model,and experiment of 2A12-T4 aluminum alloy under constant loading spectrum was carried out to validate analysis results.Semi-analytic model results show that amplitude ratio variation of smart washer increases with washer relative permeability,while decreases with washer conductivity.The result of fatigue crack monitoring experiment of 2A12-T4 aluminum alloy under constant loading spectrum verifies the damage monitoring capability of smart washer with aluminum alloy and stainless steel materials.However,monitoring curve of smart washer with stainless steel material is smoother than that with aluminum alloy material,which indicates that the smart washer with steel stainless material has a better monitoring capability.The first channel of smart washer is capable of monitoring on accumulated damage and the other three channels are capable of quantitative monitoring on fatigue crack,with monitoring precision of 1mm.