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4 Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

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Surface waves and other acoustic modes in semi-infinite anisotropic media

Alshits V. I.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

2004

Z. 81

7-44

A brief survey is presented of the theory of acoustic eigen-modes in elastic half-spaces of unrestricted anisotropy with or without piezo-electric, piezo-magnetic and magnetoelectric couplings. Existence conditions and possible numbers of different wave modes for various boundary-value problems are considered. Subsonic, supersonic, quasi-bulk and leaky surface waves as well as homogeneous and inhomogeneous exceptional bulk waves and some other modes are described. Relations between group, ray and tracing velocities of surface waves in piezolelectrics are established. The reflection problem is considered in the same terms theory of surface waves. The condition for a simple reflection is found. A resonance reflection of bulk waves with the tracing speed close to that of a leaky surface waves is discussed.

Electric componentes of acoustic fields in piezoelectrics and some their topological features

Alshits V. I., Lyubimov V. N., Radowicz A.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

2004

Z. 81

45-69

The existence conditions of zero electric fields E and zero electric displacements D are studied for bulk acoustic waves in piezoelectric crystals. General equations are derived for lines of zero electric fields, E(m) = O, and for specific points mo of vanishing electric displacements, D(mo) = O, on the unit sphere of propagation directions m2 = 1. It is proved that the both types of specific directions must exist in any (even triclinic) crystals.The obtained equations are solved for a series of examples of particular crystal symmetry. It is shown that the vectors D(m) being generally orthogonal to the wave normal m are characterized bydefinite orientational singularities in the vicinity of mo and can be described by the poincare indices n+O, +- 1 or +-2. The algebraic expressions for indices n are found both for unrestricted anisotropy and for a series of particular cases.

The peculiarities of the resonant excitations of surface elastic waves in dissipative anisotropic media

Alshits V. I., Lyubimov V. N., Radowicz A.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

1998

Z. 66

45-53

Elastic waves in absortive anisotropic media : pekuliarities of wave surfaces and singularities in the polarization fields

Alshits V. I., Lyubimov V. N.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

1998

Z. 66

15-43