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.