EXPERIMENTAL STUDY ON DYNAMIC PIEZOELECTRICITY CHARACTERISTICS OF PVDF SENSOR

The experiment study on piezoelectricity characteristics of the PVDF strain sensor between 0.1 Hz and 30 Hz is carried out and the reason why there is phase difference between PVDF strain and the output voltage of the charge amplifier within range of low frequencies is analyzed. It is observed from amplitude frequency characteristic and phase frequency characteristic that minor phase difference has little effects on the measured harmonic vibration signal but cause wave form distortion for random vibration signal. Hence within low frequency range the charge amplifier with good low frequency characteristic to match the applications of PVDF strain sensor to reduce the wave form distortion is suggested to use to measure random vibration signals.