Electric to acoustic conversion by a spherical piezoceramic shell with shields

Abstract

A problem of nonstationary hydroelectroelasticity is solved to determine the pressure in the ambient medium when a spherical thin-walled piezoelectric transducer with a shield either inside or outside is excited with an electric pulse Keywords: nonstationary hydroelectroelasticity, electric and acoustic pulses, conversion, piezoceramic spherical shell, inside and outside shields Introduction. Nowadays, the piezoelectric effect is widely used in the industry, which explains the considerable interest in piezoceramic materials and devices made from them.The widespread use of piezoceramics is due to their capability of converting mechanical energy to electric energy, and vice versa. Today, piezoceramic transducers are employed in various areas of modern technology, medicine, biology, and agriculture. They are most popular in sonar systems used in navigation safety, ocean research, marine geology, fishery, monitoring and analysis of the acoustic fields of ships and parameters of sonar equipment.Of the widest use are plate, rod, cylindrical, and spherical piezoelectric transducers. Piezoelectric plates mainly operate to receive acoustic vibrations and convert them into electric signals. Rod, cylindrical, and spherical transducers either generate or receive acoustic vibrations. Applied hydroacoustics is currently interested in the use of electric pulses with a complex law of voltage variation for the nonstationary excitation of piezoelectric transducers. The overwhelming majority of the available publications on the nonstationary hydroelectroelasticity of thin-walled piezoceramic shells studies the nonstationary behavior of cylindrical shells [1][2][3][4][5]. Those few publications that address transient modes in spherical piezoceramic shells [11], spherical piezoceramic shells with inside impedance shield [12], and two concentric spherical piezoceramic shells [1, 6] do not provide methods and a theory for the development of modern sonar systems.The present paper is concerned with the transients induced by a variable voltage in a thin-walled piezoceramic spherical shell (piezoelectric transducer) with a perfectly rigid spherical body inside (internal rigid shield) or an elastic shell inside or outside. This shielded transducer is placed in a fluid. Formulating problems of this class, developing methods to solve them, and establishing transient patterns are of current importance for modern acoustics because of the demands of advanced engineering. Note that the nonstationary electroelasticity and vibrations of cylindrical shells with a fluid were studied in [14][15][16][17].

Propagation of two-dimensional nonstationary vibrations in an electrically excited piezoceramic prismatic body

“…This distribution causes stresses in the cross-section that generate displacement waves propagating from the outside surfaces. The velocities of thickness displacements u x and planar displacements u z are determined from the problem of propagation of harmonic oscillations in a piezoelectric medium [3,6,8]: [18], i.e., the displacements on the horizontal segments in Fig. 2 are equal to those in the one-dimensional problem.…”

Pulse mode of operation of a spherical piezoceramic transducer filled with liquid and having a correcting electric circuit

“…A topic most similar to this present paper is discussed in Ref. 9, where a spherical piezoceramic shell with a spherical shield placed either inside or outside is considered. This paper is focused mainly on obtaining general solution, which, however, requires the use of computational method.…”

“…In addition, the study of Savin and Morgun, in contrast to the present study, does not consider electric circuits connected to the piezoceramic transducer. It should be noted that studies by Babaev et al, 7 Babaev et al, 8 Savin and Morgun, 9 use the equations of motion of shells in the general form as well as the method of Laplace transformation. The Laplace images in this case do not have originals in analytical forms.…”

Experimental Data on Dynamic Changes of Radio Pulses When They are Emitted by Piezoceramic Electromechanical Transducers

“…The analysis of published materials [4][5][6][7][8][9][10][11][12][13][14][15][16] indicates 06022-2 that in the design support for detecting distortions in the parameters of pulses of acoustic location systems, the greatest success was achieved in non-destructive testing [5][6][7][8][9][10][11][12][13]. This is due to the use of a simpler and more advanced numerical method for determining the parameters of pulses -the method of equivalent electromechanical circuits [4,5].…”

“…This is due to the use of a simpler and more advanced numerical method for determining the parameters of pulses -the method of equivalent electromechanical circuits [4,5]. Using this method, the influence on the parameters of pulses during emission of sound energy into solids is determined by the design parameters of the transducer [6], the multilayer design of the transducer [7,8], the electromechanical coupling coefficient of the piezoceramic parameters of the transducer [9], the shape of the transducer [10,11], correcting electric circuits [12] and the "emissionreception" system as a whole [13].…”