Effects of functionally graded interlayers on dispersion relations of shear horizontal waves in layered piezoelectric/piezomagnetic cylinders

We investigate the propagation of shear horizontal (SH) surface waves in a functionally graded magneto-electro-elastic half-space with hexagonal (6mm) symmetry. The material properties vary in the direction perpendicular to the free surface. The surface of the half-space is mechanically free, but subjected to four types of electromagnetic boundary conditions. These boundary conditions are electrically open/magnetically closed, electrically open/magnetically open, electrically closed/magnetically open and electrically closed/magnetically closed. The effects of the electromagnetic boundary conditions and the variation of material properties on the propagation characteristics of SH surface waves are analyzed. The results obtained show that except for the electrically open/magnetically closed condition, three sets of other electromagnetic boundary conditions sustain the propagation of SH surface waves. Different from the case in homogeneous materials, the existing SH surface waves in functionally graded half-spaces are dispersive.

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Effect of Initial Stress on the Behavior of Love Waves in an Elastic Half-Space with a Functionally Graded Layer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.33-37.669 ◽

2008 ◽

Vol 33-37 ◽

pp. 669-674 ◽

Cited By ~ 2

Author(s):

Zheng Hua Qian ◽

Feng Jin ◽

Kikuo Kishimoto

Keyword(s):

Initial Stress ◽

Half Space ◽

Love Wave ◽

Dispersion Relations ◽

Functionally Graded ◽

Love Waves ◽

Shear Stresses ◽

Thickness Direction ◽

Mechanical Displacement ◽

Graded Structures

The propagation behavior of Love waves in a functionally graded material layered half-space with initial stress is taken into account. The Wentzel-Kramers-Brillouin (WKB) asymptotic technique is adopted for the theoretical derivations. The analytical solutions are obtained for the dispersion relations and the distributions of mechanical displacement and stress along thickness direction in the layered structure. Firstly, these solutions are used to study effects of the initial stress on the dispersion relations and phase velocities, then influences of the initial stress on the distributions of mechanical displacement and shear stresses along thickness direction are discussed in detail. Numerical results obtained indicate that the phase velocity of Love wave increases with the increase of the magnitude of the initial tensile stress, while decreases with the increase of the magnitude of the initial compression stress. The effects on the dispersion relations of the Love wave propagation are negligible as the magnitudes of the initial stress are less than 100MPa. Some other results are shown for distributions of field quantities along thickness direction. The results obtained are not only meaningful for the design of functionally graded structures with high performance but also effective for the evaluation of residual stress distribution in the layered structures.

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