Monitoring cracks of metal structure based on grating thin-film sensor

基于格栅式薄膜传感器的金属结构裂纹监测

¹ College of Aeronautic Engineering, Air Force Engineering University, Xi'an 710038, China
² Unit 95949 of the Chinese People's Liberation Army, Cangzhou 061022, China

Received: 21 April 2021

Abstract

The hole edge of a metal structure is the most likely crack position in an aircraft structure. The quantitative monitoring of a hole-edge crack is important for structural health monitoring. Therefore, this paper presented a grating thin-film sensor based on the potentiometric method. Firstly, the anodic oxidation process was used to prepare thin film on 2A12-T4 aluminum alloy matrix to prevent the aluminum alloy matrix from interfering with the monitoring signal of the sensor. Then the DC superimposed pulsed bias arc ion plating technique was used to prepare the grating thin-film sensor on the surface of the specimen. The output characteristics of the grating thin-film sensor are obtained with its finite element model, and the factors affecting the sensitivity of the sensor are analyzed. Finally, the fatigue crack monitoring tests were carried out to verify the quantitative monitoring capability of the grating thin film sensor. The experimental results show that it is feasible for the grating thin-film sensor to quantitatively monitor the fatigue crack at the hole edge of an aircraft metal structure.

摘要

金属结构孔边是飞机结构中最容易出现裂纹的位置，实现金属结构孔边裂纹的定量监测是结构健康监测领域的重要研究内容，因此提出了一种基于电位法的格栅式薄膜传感器。采用阳极氧化工艺在2A12-T4铝合金基体上制备了Al₂O₃薄膜以防止金属基体对传感器监测信号造成干扰，然后采用直流叠加脉冲偏压电弧离子镀技术在表面制备了格栅式薄膜传感器；通过建立格栅式薄膜传感器的有限元模型，得到传感器的输出特性，分析研究了传感器灵敏度的各影响因素；开展疲劳裂纹监测试验，验证了格栅式薄膜传感器的疲劳裂纹定量监测能力。试验结果表明，格栅式薄膜传感器具有应用于飞机金属结构孔边疲劳裂纹定量监测的可行性。