Complex Rayleigh Waves in Nonhomogeneous Magneto-Electro-Elastic Half-Spaces

Abstract

The complex Rayleigh waves play an important role in the energy conversion efficiency of magneto-electro-elastic devices, so it is necessary to explore the wave propagation characteristics for the better applications in engineering. This paper modifies the Laguerre orthogonal polynomial to investigate the complex Rayleigh waves propagating in nonhomogeneous magneto-electro-elastic half-spaces. The improved method simplifies the calculation process by incorporating boundary conditions into the constitutive relations, shortens the solving time by transforming the solution of wave equation to an eigenvalue problem, and obtains all wave modes, including real and imaginary and complex wavenumbers. The three-dimensional curves of full frequency spectrum and phase velocities are presented for the better description of the conversion from complex Rayleigh wave modes to real wave ones; besides, the displacement distributions, electric and magnetic potential curves are obtained in thickness and propagation directions, respectively. Numerical results are analyzed and discussed elaborately in three cases: variation of nonhomogeneous coefficients, absence of magnetism, and absence of electricity. The results can be used to optimize and fabricate the acoustic surface wave devices of the nonhomogeneous magneto-electro-elastic materials.

Influence of the Schottky Junction on the Propagation Characteristics of Shear Horizontal Waves in a Piezoelectric Semiconductor Semi-Infinite Medium

“…where k L and ω L are the apparent wave number component and angular frequency of the shear horizontal wave in the lower n-type PSC substrate, respectively. Based on the spectral method [25][26][27], the Laguerre polynomials Q m are used to expand these three undetermined amplitudes U L z , U L φ , and U L n , which are all functions of the space coordinate…”

“…Two biasing electric fields are further considered in the basic equations of the lower n-type PSC substrate, which provides evident influence on the physical properties of the Schottky junction. Then, through the spectral method [25][26][27], two equivalent mathematical models are established to investigate the dispersion and attenuation characteristics of the shear horizontal wave that propagates in this PSC semiinfinite medium, instead of the state transfer equation method. Searching for complex roots of complex transcendental equations can be avoided, and the numerical calculation of the dispersion and attenuation curves of the shear horizontal wave is transformed into solving the eigenvalues.…”

Thermal Contact Response of a Transversely Isotropic Magneto-Electro-Elastic Coating

“…Owing to the multiple excellent coupled properties of mechanics, electricity and magnetism, a magneto-electro-elastic (MEE) material can convert energy from one to the other, making it widely used in sensors, transducers, generators, and medical equipment as an intelligent structure [ 1 , 2 , 3 , 4 ]. In practical engineering applications, the MEE material is usually applied in sensing and driving devices in the form of a thin film or layered structure [ 5 , 6 , 7 ], where friction contact occurs inevitably on its surface [ 8 ].…”

Surface Roughness Effects on Self-Interacting and Mutually Interacting Rayleigh Waves

“…Both linear and nonlinear Rayleigh wave measurements require sensors that send and receive the waves at ultrasonic frequencies. Recent studies of Rayleigh wave measurements include Ghafoor et al [ 19 ], Li et al [ 20 ], Song et al [ 21 ], Li et al [ 22 ], and Sarris et al [ 23 ]. Many types of sensors can be used for this purpose including angle-beam, comb, interdigitated, and pulsed lasers.…”