The phenomena of reflection and transmission waves in smart nano materials

Abstract

In this paper, the basic equations (equations of motion and Gauss equations) and constitutive relations for the smart materials (piezoelectric media) have been written. By solving a set of linear algebraic equations, we have obtained the reflection and refraction coefficients when incident different kinds of waves such as (qSV and φ-mode) falling upon the interface between two different anisotropic piezoelectric media (each of them has hexagonal symmetry). Numerical calculations are performed when the lower medium is Zinc Oxide (ZnO) while the upper medium is PZT-2 Ceramic. Numerical results of the reflection and refraction coefficients are analytically obtained and presented graphically. It is found that different kinds of reflected and refracted waves are produced which may be organized as follow: (i) Two reflected elastic waves in the lower medium, one of them is qP wave and the other is qSV wave and similar of them but refracted waves in the upper medium. (ii) Two reflected potential electric waves in the lower medium and similar of them but refracted waves in the upper medium. It is noticed that the reflected and refracted coefficients of the last kinds waves are proportional to the reflected and refracted coefficients of the first kinds of waves. Furthermore, the parameters of the proportional are functions of the incident angles. Moreover, it is observed that the amplitudes ratios of reflection and transmission coefficients depend upon the angle of incidence, the parameters of electric potential and elastic constants of the media. This study is very useful in signal processing, sound system and wireless communication in addition to improvement of SAW wave devices and military defense equipment. PM3 molecular modeling method was used to describe the geometrical and physical properties of PZT-ZnO composite. Results indicate the occurrence of this composite in nano scale. Copyright © 2011 American Scientific Publishers.