Frequrncy response characterization

The fabricated device is characterized for its dynamic properties. The characterization setup is as follows. This piezoelectric buzzer is, in turn, attached to a rigid block using double-sided tape. Now, the piezo buzzer is actuated, and the response of the device is captured by the stroboscope software of Polytec vibrometer. Since a base excitation is given to the device, the relative displacement (displacement of the proof mass minus the displacement of the piezoelectric actuator) is represented in the Bode plot. The theoretical natural frequency is 289 Hz. And the experimentally observed resonant frequency is 268 Hz, as it can be seen that there is a phase change of 180 degree at 268 Hz. The Q factor determined by the 3 dB bandwidth method is 335, so the slide film damping coefficient, c, is estimated to be 6.05e-10 Ns/m.针对所制备的器件（fabricated device）开展动态特性表征，表征装置搭建如下。该压电蜂鸣器（piezoelectric buzzer）通过双面胶带固定于刚性块体之上。启动压电蜂鸣器后，借助Polytec激光测振仪的频闪软件采集器件的响应信号。由于对器件施加了基础激励，将相对位移（relative displacement，即质量块（proof mass）位移与压电驱动器（piezoelectric actuator）位移的差值）以波特图（Bode plot）形式呈现。该器件的理论固有频率（theoretical natural frequency）为289 Hz；实验测得的共振频率为268 Hz，可观测到在该频率处存在180°的相位突变（phase change）。采用3dB带宽法（3 dB bandwidth method）确定的品质因数（Q factor）为335，据此估算得到滑膜阻尼系数（slide film damping coefficient）c为6.05×10^-10 N·s/m。