Tunable band gaps and transmission behavior of SH waves with oblique incident angle in periodic dielectric elastomer laminates

2018 ◽  
Vol 146-147 ◽  
pp. 81-90 ◽  
Author(s):  
Jun Zhu ◽  
Haoyun Chen ◽  
Bin Wu ◽  
Weiqiu Chen ◽  
Oluwaseyi Balogun
Keyword(s):  
Incident Angle ◽  
Dielectric Elastomer ◽  
Band Gaps ◽  
Sh Waves

scholarly journals Band gap manipulation of viscoelastic functionally graded phononic crystal

2020 ◽  
Vol 9 (1) ◽  
pp. 515-523
Author(s):  
Zuguang Bian ◽  
Shuai Yang ◽  
Xiaoliang Zhou ◽  
David Hui
Keyword(s):  
Incident Angle ◽  
Phononic Crystal ◽  
Functionally Graded ◽  
Band Gaps ◽  
Heat Sources ◽  
Initial State ◽  
Final State ◽  
Sh Waves ◽  
Numerical Examples ◽  
The Matrix

AbstractIn this study, band gaps of SH-waves (horizontally polarized shear waves) propagating in a thermal-sensitive viscoelastic matrix are investigated. Metallic films acting as heat sources are periodically embedded into the matrix, which establishes a periodically inhomogeneous thermal field. The homogenous matrix is therefore transformed into functionally gradient phononic crystals (PCs). A three-parameter solid model is employed to describe the viscoelasticity of the present matrix. By virtue of a transfer matrix method incorporated within a laminated model, the dispersion equation of SH-waves is finally obtained, from which the band gaps are determined. The transmission spectra of a finite-periodic PC are also solved to validate the band gaps. In numerical examples, the influences of incident angles of SH-waves and viscoelasticity of matrix on band gaps are discussed first. Then the research focuses on the means to tune the band gaps by manipulating the inputted powers of heat sources. Numerical examples demonstrate that such a strategy is effective and convenient in tuning the positions and widths of band gaps. A viscous parameter, i.e., the ratio of initial-state to final-state storage moduli, significantly affects the band locations and bandwidths, while the locations of low-order band gaps hardly move with the incident angle of SH-waves. Band gaps of several orders are expected to locate in lower-frequency domain, and the total bandwidth becomes larger as the inputted heat flux increases. This paper lays theoretical foundation to manufacture viscoelastic functionally graded PCs which can be used in frequency-selective devices.

Reflection and transmission of SH waves at a very rough interface and its band gaps

2017 ◽  
Vol 411 ◽  
pp. 422-434 ◽  
Author(s):  
Pham Chi Vinh ◽  
Tran Thanh Tuan ◽  
Do Xuan Tung ◽  
Nguyen Thi Kieu
Keyword(s):  
Band Gaps ◽  
Rough Interface ◽  
Reflection And Transmission ◽  
Sh Waves

Wave Scattering of Plane P, SV, and SH Waves by a 3D Alluvial Basin in a Multilayered Half-Space

2020 ◽  
Vol 110 (2) ◽  
pp. 576-595 ◽  
Author(s):  
Zhenning Ba ◽  
Ying Wang ◽  
Jianwen Liang ◽  
Vincent W. Lee
Keyword(s):  
Half Space ◽  
Incident Angle ◽  
Plane Waves ◽  
Single Layer ◽  
Fundamental Solutions ◽  
New Method ◽  
General Applicability ◽  
Sh Waves ◽  
Sedimentary Sequences ◽  
Homogeneous Half Space

ABSTRACT A special indirect boundary element method (IBEM) is proposed to investigate the waves scattering of plane P, SV, and SH waves by a 3D alluvial basin embedded in a multilayered half-space. The new IBEM, which uses half-space Green’s functions for uniformly distributed loads acting on an inclined plane as its fundamental solutions, has the merits of (1) excellent capability of dealing with the stratification of the basin and the external half-space, (2) without the problem of singularity due to fictitious distributed loads being directly applied on the real boundaries, and (3) good adaptability to complex models with trapezoidal or triangular elements being used to discretize the boundaries. The validity and accuracy of the new method are verified by comparing its results with those in the literature. To illustrate the general applicability and efficiency of the new method further, 3D alluvial basins of varying shapes, depths, and sedimentary sequences embedded in a single layer overlying a homogeneous half-space are numerically studied. Numerical results show that the basin’s shape, depth, and sedimentary sequence all have significant impact on the ground seismic responses; the incident angle also has noticeable effects on the surface motion, and these effects are more prominent at the observation points along the incident direction of the plane waves; for the case of layered model, the displacement spectral amplification is affected by the eigenmodes of the vibrations of the layers, both inside and outside the basin.

Elastic Wave Band Structures and Defect States in a Periodically Corrugated Piezoelectric Plate

2014 ◽  
Vol 81 (8) ◽  
Author(s):  
Y. Huang ◽  
C. L. Zhang ◽  
W. Q. Chen
Keyword(s):  
Symmetry Breaking ◽  
Piezoelectric Plate ◽  
Band Gaps ◽  
Wave Band ◽  
Plane Wave Expansion ◽  
Defect States ◽  
Band Structures ◽  
Sh Waves ◽  
Different Types ◽  
Shear Horizontal

The band structures of shear horizontal (SH) waves in a periodically corrugated piezoelectric plate (PCPP) are studied by using the supercell plane wave expansion (SC-PWE) method. The effect of plate symmetry on the defect state caused by a defect in the plate is investigated in detail. The PCPPs with different types of symmetry give rise to different kinds of band gaps and the associated defect states. The increase of defect size lowers the frequency of defect bands, and it can be used to tune the narrow-passband frequencies in acoustic band gaps. Symmetry breaking is also introduced by reducing the lower corrugation depth of the PCPP. Results show that symmetry breaking leads to both the appearance and disappearance of new kinds of gaps and the corresponding defect bands in these gaps.

Magnetized plasma photonic crystals band gap

2014 ◽  
Vol 80 (4) ◽  
pp. 581-592 ◽  
Author(s):  
Elahe Ataei ◽  
Mehdi Sharifian ◽  
Najmeh Zare Bidoki
Keyword(s):  
Magnetic Field ◽  
Band Gap ◽  
Incident Angle ◽  
Band Gaps ◽  
Photonic Band Gaps ◽  
Main Band ◽  
One Dimensional ◽  
Plasma Photonic Crystal ◽  
Photonic Band ◽  
The Magnetic Field

In this paper, the effect of the magnetic field on one-dimensional plasma photonic crystal band gaps is studied. The one-dimensional fourfold plasma photonic crystal is applied that contains four periodic layers of different materials, namely plasma1–MgF2–plasma2–glass in one unit cell. Based on the principle of Kronig–Penney's model, dispersion relation for such a structure is obtained. The equations for effective dielectric functions of these two modes are theoretically deduced, and dispersion relations for transverse electric (TE) and transverse magnetic (TM) waves are calculated. At first, the main band gap width increases by applying the exterior magnetic field. Subsequently, the frequency region of this main band gap transfers completely toward higher frequencies. There is a particular upper limit for the magnitude of the magnetic field above which increasing the exterior magnetic field strength doesn't have any significant influence on the dispersion function behavior. (With an increase in incident angle up to θ1= 66°, the width of photonic band gap (PBG) changes for both TM/TE polarization.) With an increase in incident angle up to θ1= 66°, the width of PBG decreases for TM polarization and the width of PBG increases for TE polarization, but it increases with further increasing of the incident angle from θ1= 66° to 89° for both TE- and TM-polarizations. Also, it has been observed that the width of the photonic band gaps changes rapidly by relative difference of the two-plasma frequency. Results show the existence of several photonic band gaps that their frequency and dispersion magnitude can be controlled by the exterior magnetic field, incident angle, and two plasma frequencies. The result of this research would provide theoretical instructions for designing filters, microcavities, fibers, etc.

scholarly journals Transmission and band gaps of elastic SH waves in functionally graded periodic laminates

2012 ◽  
Vol 49 (2) ◽  
pp. 344-354 ◽  
Author(s):  
M.V. Golub ◽  
S.I. Fomenko ◽  
T.Q. Bui ◽  
Ch. Zhang ◽  
Y.-S. Wang
Keyword(s):  
Functionally Graded ◽  
Band Gaps ◽  
Sh Waves

scholarly journals Scattering of Antiplane SH Waves by Complex Landforms

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Menghan Sun ◽  
Hui Qi
Keyword(s):  
Incident Angle ◽  
Complex Function ◽  
Surface Displacement ◽  
Complex Model ◽  
Barrier Effect ◽  
Algebraic Equations ◽  
Multiple Reflections ◽  
Sh Waves ◽  
Order Bessel Function ◽  
Incident Frequency

The multiple scattering of SH waves by isosceles triangular hill, semicircle depression, and isosceles trapezoidal hill in the solid half-space is studied. The complex model is divided into multiple subdomains by using the region matching method, then the wave functions in each subdomain are constructed by using the fractional-order Bessel function, and finally, the infinite algebraic equations for solving the unknown coefficients in the wave function are established by using the multipolar coordinate technique and the complex function method according to the boundary conditions. Fourier series is used to solve the unknown undetermined coefficients. The results show that due to the multiple reflections of the incident wave between complex landforms, surface displacement amplitude is affected by the incident angle, incident frequency, and the distance between the isosceles triangular hill, semicircle depression, and isosceles trapezoidal hill. It is found that when the incident frequency increases, there is a certain amplification effect between the hills and the depression. When the wave is incident horizontally, there is a certain “barrier” effect between hills and depression, and when the distance between the hills and depression reaches a certain level, the “barrier” effect will reach a stable value.

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