固有频率压电堆激励无损测量方法

提出一种利用压电堆激励测量结构固有频率的方法，该方法利用压电堆产生纳米级微小振动对结构进行扫频激励。与传统的采用振动台激励、锤击等固有频率测量方法相比，所提出的方法激振幅度小，对于阻尼小、品质因数高且达到共振频率时位移放大系数大的结构，也不会产生破坏。设计了品质因数很高的悬臂梁结构进行实验，为准确探测微小振动信号，采用电涡流传感器测量位移，并使用锁定放大器提高信噪比。仿真与实验数据表明，该方法准确有效，可实现对结构固有频率的无损测量。

Nondestructive measurement of natural frequency by excitation of a piezoelectric stack

A method of measuring natural frequency by excitation of a piezoelectric stack is proposed. In comparison with the traditional method that using a vibrating table or a hammer, the proposed method is nondestructive to the structure even when the structural damping is small and the displacement magnification factor is large, because the amplitude of the vibration is controlled to be exceptionally small. A cantilever of a high Q factor is designed to verify the method. An eddy current sensor and a lock-in amplifier are utilized to detect the displacement of the cantilever. The finite element analysis and the experimental result show that the proposed method can measure the natural frequency without destruction to the structure effectively.