Studies on strain sensing properties of PVDF piezoelectric films

PVDF is a kind of piezoelectric film with soft texture, high sensitivity, fast response, wide frequency bandwidth and other advantages. There are few reports on the output characteristics of piezoelectric thin films under applied stress. In this paper, the sensing mechanism of PVDF piezoelectric film is analyzed theoretically. And then a numerical model set up by COMSOL software is applied to simulate the piezoelectric film. The content of the simulation is to study the variation of the output signal of the film when changing the excitation frequency, vibration amplitude and the applied stress of the exciting source. Finally, the dynamic responses of PVDF piezoelectric films with different parameters are studied experimentally. Numerical and experimental results both showed that the output signal amplitude of piezoelectric film is proportional to the amplitude of excitation, but not directly related to the external stress of the film.