Theory and performance of acoustical dispersive surface wave delay lines

2015

OJA

This comparative study acquaints the reader with some properties of the eighth and tenth new shear-horizontal surface acoustic waves (SH-SAWs) propagating along the free surface of the magnetoelectroelastic (6 mm) medium. These new nondispersive SH-SAWs cannot exist when the electromagnetic constant α is equal to zero. The piezoelectromagnetic SH bulk acoustic wave and the surface Bleustein-Gulyaev-Melkumyan (BGM) wave are also chosen for comparison. The main problem of this report is the demonstration of the fact that the new waves can propagate slower than the BGM wave. This problem can be very important due to the fact that among the other known SH-SAWs the BGM wave can propagate significantly slower than the corresponding SH bulk acoustic wave. Two new SH-SAWs are analytically and graphically studied in dependence on the electromagnetic constant α. For the graphical study, two (6 mm) composites are used: BaTiO3-CoFe 2 O 4 and PZT-5H-Terfenol-D. For the second composite it is solidly demonstrated that for small values of α, the eighth new SH-SAW cannot exist and its velocity starts with zero at some small threshold value of α rapidly reaching the BGM-wave velocity. This means that a weak magnetoelectric effect can dramatically slow down the speed of either new SH-SAW. As a result, the studied new SH-SAWs can be suitable for creation of new technical devices to sense the magnetoelectric effect. For the analytical study, extreme and inflexion points were evaluated in the velocities' dependencies on the value of the electromagnetic constant α. Keywords Magnetoelectroelastics, Magnetoelectric Effect, New SH-SAW, Bleustein-Gulyaev-Melkumyan Wave A. A. Zakharenko 74

Section: Introductionmentioning

confidence: 99%

Dramatic Influence of the Magnetoelectric Effect on the Existence of the New SH-SAWs Propagating in Magnetoelectroelastic Composites

2015

OJA

“…However, the SH-wave speed in such propagation directions must be the same because this is the transversely isotropic case. Note that the high symmetry propagation directions are well-known and can be also found in [56] [57]. Also, it is worth noting that in the high symmetry propagation direction, the following independent nonzero material parameters exist: the stiffness constant C, piezomagnetic coefficient h, piezoelectric constant e, dielectric permittivity coefficient ε, magnetic permeability coefficient μ, and electromagnetic constant α, where C = C 44 = C 66 , e = e 16 = e 34 , h = h 16 = h 34 , ε = ε 11 = ε 33 , μ = μ 11 = μ 33 , and α = α 11 = α 33 [53]- [55], see also the famous books cited in [58] [59].…”

Section: Theory and Resultsmentioning

confidence: 93%

Investigation of SH-Wave Fundamental Modes in Piezoelectromagnetic Plate: Electrically Closed and Magnetically Closed Boundary Conditions

2014

OJA

“…The upper and lower surfaces of the plate are then situated at x 3 = +d and x 3 = -d, respectively. This is the case of the propagation of pure SH-wave [14] [15]. To study the propagation of the SH-wave coupled with both the electrical and magnetic potentials, the quasi-static approximation [8] [9] [14]- [16] must be utilized.…”

Section: Theory Of Finding Of Eigenvalues and Eigenvectorsmentioning

confidence: 99%

On New Dispersive SH-Waves Propagating in Piezoelectromagnetic Plate

2015

OJA

This theoretical work discovers four new dispersive shear-horizontal (SH) waves propagating in the transversely isotropic piezoelectromagnetic plate of class 6 mm. In this work, the following mechanical, electrical, and magnetic boundary conditions at both the upper and lower free surfaces of the piezoelectromagnetic plate are utilized: the mechanically free surface, continuity of both the electrical and magnetic potentials, and continuity of both the electrical and magnetic inductions. The solutions for the new SH-wave velocities (dispersion relations) are found in explicit forms and then graphically studied. The graphical investigation has soundly illuminated several interesting peculiarities that were also discussed. The piezoelectromagnetic materials, also known as the magnetoelectroelastic media, are famous as smart materials because the electrical subsystem of the materials can interact with the magnetic subsystem via the mechanical subsystem, and vice versa. Therefore, it is very important to know the wave characteristics of such (composite) materials because of possible constitution of new technical devices with a high level of integration. It is obvious that the plate waves can be preferable for further miniaturization of the technical devices and used for the nondestructive testing and evaluation of thin piezoelectromagnetic films.