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

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: Analytical Studymentioning

confidence: 99%

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

2015

OJA

“…Obtained Equations (29) and (35) in the third and fourth sections, respectively, are final and have suitable forms for further numerical study. For the calculations, the material parameters can be borrowed from reference [39][40][41][42]. Let us use the material parameters for two piezoelectromagnetic materials (composites BaTiO 3 -CoFe 2 O 4 and PZT-5H-Terfenol-D) given in references [39,40].…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…For the calculations, the material parameters can be borrowed from reference [39][40][41][42]. Let us use the material parameters for two piezoelectromagnetic materials (composites BaTiO 3 -CoFe 2 O 4 and PZT-5H-Terfenol-D) given in references [39,40]. The PZT-5H-Terfenol-D material parameters are: C = 1.45 × First of all, it is natural to contemplate the velocity V new5 of the fifth new SH-SAW given by Equation (26) and discovered in book [21] several years ago.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

On Discovery of the Twelfth and Thirteenth New Nondispersive SH-SAWs in 6 mm Magnetoelectroelastics

2019

Acoustics

This report acquaints the reader with an extra two new shear-horizontal surface acoustic waves (SH-SAWs). These new SH-SAWs can propagate along the free surface of the transversely isotropic (6 mm) magnetoelectroelastic materials. These (composite) materials can simultaneously possess the piezoelectric, piezomagnetic, and magnetoelectric effects. Some competition among these effects can lead to suitable solutions found for the following three possible coupling mechanisms: eα – hε, eµ – hα, εµ – α2. Here, the mechanically free interface between the solid and a vacuum was considered. This report discovers the twelfth (thirteenth) new SH-SAW for the magnetically closed (electrically open) case and continuity of both the normal component of the electrical (magnetic) displacement and the electrical (magnetic) potential when the coupling mechanism eα – hε (eµ – hα) works. The propagation velocities were obtained in explicit forms that take into account the contribution of the vacuum material parameters. The discovered waves were then graphically studied for the purpose of disclosing the dissipation phenomenon (the propagation velocity becomes imaginary) caused by the coupling with the vacuum properties. The obtained results can be useful for further investigations of interfacial and plate SH-waves, constitution of technical devices, nondestructive testing and evaluation, and application of some gravitational phenomena.

On separation of exchange term from the coefficient of the magnetoelectromechanical coupling

2016

Pramana - J Phys

The purpose of this analysis is to introduce the separated exchange coefficient and to graphically investigate it. This coefficient, depending on the electromagnetic constant plus two coefficients of the electromechanical and magnetomechanical couplings, form the coefficient of magnetoelectromechanical coupling (CMEMC), a very important characteristic used for analysing magnetoelectroelastic smart (composite) materials. It was analytically and graphically demonstrated that the CMEMC can have a minimum due to the minimum of the exchange coefficient at a certain value of the electromagnetic constant. For graphical investigation, the frequently used transversely isotropic (6mm) composite materials such as BaTiO 3 -CoFe 2 O 4 and PZT-5H-Terfenol-D are exploited.