ABOUT ANALYTICAL UNCERTAINTY THE COMPONENT OF THE TENSOR OF POWER ELECTROMECHANICAL FORCE FACTORS FOR FILM POLYMERIC PIEZO MATERIAL

Abstract

Currently, piezoelectric materials based on films, for example, polyvinylidene fluorides, have found
wide application in various industries. The interest in these materials is justified, first of all, by the advantageous,
in comparison with materials based on piezoceramic compositions, values of the density of the
film material, as well as the values of the effective piezoelectric coefficients, which makes it possible to implement new principles of loading in products in order to convert mechanical energy into electrical
energy. In addition, the lower rigidity of film polymer materials, compared to the rigidity of sensitive elements
of electroacoustic transducers based on piezoceramic compositions, makes it possible to create
designs of large-area transducers or antenna apertures assembled from these transducers, repeating the
contours of carrier housings. The article describes the prospects for the introduction of film polymer
piezomaterials into hydroacoustic and electric generating equipment products. Obviously, the introduction
of new materials into hydroacoustic and piezoelectric generator technology requires a rethinking of methods
for calculating the characteristics of products based on film piezoactive materials. One of the main
characteristics of electroacoustic transducers, used both in hydroacoustic technology and in products for
generating electrical energy through the use of sea or ocean surface waves, is the energy coefficient of
electromechanical coupling. The specified coefficient is a tensor physical quantity, and, accordingly, for
anisotropic materials, which are piezoactive films, for example, from polyvinylidene fluorides, a mathematical
apparatus is needed that would allow determining the components of the tensor of the energy coefficient
of electromechanical coupling during the design of hydroacoustic and piezoelectric generator
products. An attempt to develop such a mathematical apparatus was made by the authors of the article,
but in the course of the work performed, the analytical uncertainty of the components of the tensor of the
energy coefficient of electromechanical coupling was established. The article presents a scientific substantiation
of the identified analytical uncertainty of the components of the tensor of the energy coefficient of
electromechanical coupling from equations that establish the dependence of these components on coefficients
characterizing the mechanical and piezoelectric properties of film materials, taking into account
their anisotropy.