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为满足飞机结构裂纹扩展定量化监测和工程化应用的需求,探索MWM(Meandering Winding Magnetometer)传感器进行结构健康监控的可行性,设计了一种贴附式涡流阵列传感器并为传感器的工程化应用开展了仿真优化和实验研究。基于裂纹扩展分段监测的思路,传感器的感应线圈和激励线圈采用阵列化设计。通过将材料的电导率提取为结构的等效损伤参数,构建了传感器损伤监测正向半解析模型,并对线圈厚度和基材层厚度进行了优化。为验证传感器的监测能力,开展了程序载荷谱下的2A12-T4铝合金阳极氧化试件的疲劳裂纹扩展监测实验。仿真优化结果表明,传感器监测灵敏度随提离距离的增加而减小,传感器最优工作频率范围为0.3~0.7MHz。裂纹扩展监测实验结果表明,贴附式涡流传感器具备对金属结构进行实时损伤监测的能力,感应线圈的阵列化布置方式实现了裂纹扩展的定量监测,精度达到毫米级,同断口分析结果相比,平均监测误差为3.85%。
In order to meet the requirement of quantitative monitoring and engineering application of crack propagation in aircraft structures, the feasibility of monitoring the structure health of MWM (Meandering Winding Magnetometer) sensors was explored. An attached vortex array sensor was designed and applied to the engineering application of sensors Simulation optimization and experimental research. Based on the idea of crack propagation monitoring, the sensor induction coil and excitation coil are arrayed. By extracting the conductivity of the material as the equivalent damage parameter of the structure, a forward semi-analytical model of the sensor damage monitoring is constructed, and the thickness of the coil and the thickness of the substrate layer are optimized. In order to verify the monitoring ability of the sensor, the fatigue crack propagation monitoring experiment of 2A12-T4 aluminum alloy anodized specimen under the program load spectrum was carried out. The simulation results show that the sensitivity of sensor monitoring decreases with the increase of lift-off distance, and the optimum operating frequency range of the sensor is 0.3 ~ 0.7MHz. The experimental results of crack propagation monitoring show that the attached eddy-current sensor has the ability of real-time damage monitoring of the metal structure. The array arrangement of the induction coil realizes the quantitative monitoring of crack propagation with the accuracy of millimeter. Compared with the results of fracture analysis, The average monitoring error is 3.85%.