The Study Of PVDF Hydrophone

Piezoelectric PVDF(Polyvinylidene fluoride)film is a new type of piezoelectric transducer material.It has ferroelectricity,piezoelectricity and pyroelectricity.It not only has a wide frequency response,wide dynamic range,high sensitivity,low density,low acoustic impedance and easily for processing compared with traditional piezoelectric material,but also has excellent mechanical performance such as light weight,soft,unbreakable,good impact resistance,easy made into any shape,such as irregularly shaped pieces or tubular.PVDF is normally attached to the backing to increase mechanical strength.PVDF hydrophones were studied in this paper.Firstly,the open circuit voltage of a large area planar piezoelectric PVDF film is derived within small amplitude to obtain the low frequency receiving sensitivity level of PVDF hydrophone while acoustic wave incidenting on its surface;Secondly,this paper derived the low frequency electroacoustic sensitivity of the composite piezoelectric polymer cylinder where the PVDF film is attached to a hollow cylindrical.Harmonic response analysis,modal analysis of large area PVDF hydrophones and cylinder hydrophone are simulated using finite element analysis software ANSYS.The influence of backing material properties,thickness and size of each structure to the performance of PVDF hydrophone has been analyst combined with theory.By optimizing the design and size of the virtual prototype,modal analysis and harmonic response analysis of the virtual prototype has been done in this paper.The first-order anti-resonance frequency of planar PVDF hydrophones virtual prototype is 5.2kHz,receiving sensitivity level is-199.1 dB;The first-order anti-resonance frequency of cylinder PVDF hydrophone is 5.5kHz,receiving sensitivity level is-191.6dB.Finally,planar and cylinder PVDF hydrophones were made,and their water receiving sensitivity and directivity diagram were measured.The receiver sensitivity level of planar PVDF hydrophone matches well with simulation results,ups and downs is-0.5dB and 3.2dB;the receiving sensitivity level of the cylindrical PVDF hydrophone is lower than the theoretical value,ups and downs is 3.9dB and 8.4dB,there are corresponding error analysis in the text.