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采用一种压电双晶片悬臂梁结构作为结冰探测的传感元件,使用有限元方法(FEM)计算其在有水附着与结冰两种状态下的谐振频率变化,同时使用Agilent 35670A动态信号分析仪与传统的传输法进行实验测量,通过误差对比检验计算结果的正确性,并找出谐振频率的变化与压电梁局部质量和刚度等结构特征改变之间的联系,发现随着结冰的发生以及厚度的增加,相应的局部质量和刚度的改变对谐振频率的综合影响多变。针对压电双晶片悬臂梁结构的特殊性,采用一种反馈法接线进行测量,并与传输法测量结果以及FEM计算结果进行比较,证明这种测量方法的准确性。最后根据计算与实验测量结果确定合适的工作模态,总结整个结冰过程对该模态谐振频率的影响。结果表明,压电双晶片悬臂梁结构用于结冰探测是可行的,它能够准确检测出不同结冰状态对其结构特征的影响,并且结构简单、便于测量。
A piezoelectric bimorph cantilever structure was used as the sensing element for icing detection. The finite element method (FEM) was used to calculate the resonant frequency of the icing in both water-attached and icy conditions. The Agilent 35670A dynamic signal The experimental results show that the change of resonant frequency and the change of structural characteristics such as local mass and stiffness of piezoelectric beam can be found out. And the increase of thickness, the corresponding influence of local mass and stiffness on the synthetical influence of resonant frequency varies. Aiming at the peculiarity of the piezoelectric bimorph cantilever beam structure, a kind of feedback method is adopted to measure the cantilever structure. Compared with the transmission method and the FEM calculation result, the accuracy of this method is proved. Finally, according to the calculation and experimental measurement results to determine the appropriate working mode, summarizes the entire freezing process on the modal resonance frequency. The results show that the piezoelectric bimorph cantilever structure is feasible for icing detection. It can accurately detect the influence of different icing conditions on its structural characteristics, and has the advantages of simple structure and easy measurement.