Simplified description of out-of-plane waves in thin annular elastic plates

2013 ◽  
Vol 332 (4) ◽  
pp. 894-906 ◽  
Author(s):  
Maziyar N. Zadeh ◽  
Sergey V. Sorokin
Keyword(s):  
Plane Waves ◽  
Elastic Plates ◽  
Out Of Plane

Optimization of Phononic Crystals for the Simultaneous Attenuation of Out-of-Plane and In-Plane Waves

2011 ◽  
Author(s):  
Osama R. Bilal ◽  
Mahmoud I. Hussein
Keyword(s):  
Genetic Algorithm ◽  
Phononic Crystal ◽  
Plane Waves ◽  
Phononic Crystals ◽  
Gap Size ◽  
Two Dimensional ◽  
Dispersion Characteristics ◽  
Out Of Plane ◽  
Optimization Methodology ◽  
Application Specific

The topological distribution of the material phases inside the unit cell composing a phononic crystal has a significant effect on its dispersion characteristics. This topology can be engineered to produce application-specific requirements. In this paper, a specialized genetic-algorithm-based topology optimization methodology for the design of two-dimensional phononic crystals is presented. Specifically the target is the opening and maximization of band gap size for (i) out-of-plane waves, (ii) in-plane waves and (iii) both out-of-plane and in-plane waves simultaneously. The methodology as well as the resulting designs are presented.

scholarly journals Robust separation of topological in-plane and out-of-plane waves in a phononic crystal

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Myung-Joon Lee ◽  
Il-Kwon Oh
Keyword(s):  
Elastic Wave ◽  
Phononic Crystal ◽  
Plane Waves ◽  
Degree Of Freedom ◽  
Wave Separation ◽  
Simultaneous Control ◽  
Accidental Degeneracy ◽  
Out Of Plane ◽  
Wave Path ◽  
The Rich

AbstractValley degree of freedom, associated with the valley topological phase, has propelled the advancement of the elastic waveguide by offering immunity to backscattering against bending and weak perturbations. Despite many attempts to manipulate the wave path and working frequency of the waveguide, internal characteristic of an elastic wave such as rich polarization has not yet been utilized with valley topological phases. Here, we introduce the rich polarization into the valley degree of freedom, to achieve topologically protected in-plane and out-of-plane mode separation of an elastic wave. Accidental degeneracy proves its real worth of decoupling the in-plane and out-of-plane polarized valley Hall phases. We further demonstrate independent and simultaneous control of in-plane and out-of-plane waves, with intact topological protection. The presenting procedure for designing the topologically protected wave separation based on accidental degeneracy will widen the valley topological physics in view of both generation mechanism and application areas.

scholarly journals PARTIAL WAVE BASIS ADAPTED TO EXTERIOR BOUNDARY CONDITIONS OF AN ELASTIC PLATE

2021 ◽  
Vol 20 (1) ◽  
pp. 35-43
Author(s):  
Sergiu Cojocaru ◽  
Keyword(s):  
Boundary Conditions ◽  
Elastic Plate ◽  
Functional Form ◽  
Standard Treatment ◽  
Plane Waves ◽  
Equation Of Motion ◽  
Elastic Vibration ◽  
Vibration Modes ◽  
Elastic Plates ◽  
Partial Waves

An approach to describing normal elastic vibration modes in confined systems is presented. In a standard treatment of the problem, the displacement field is represented by a superposition of partial waves of a general form, e.g., plane waves. The unknown coefficients of superposition are then obtained from the equation of motion and the full set of boundary conditions. In the proposed approach, the functional form of partial waves is chosen in such a way as to satisfy the boundary conditions on exterior surfaces identically, i.e., even if the unknown quantities determined by the remaining constraints are found in an approximation, numerically or analytically. Some examples of solutions for composite elastic plates are discussed to illustrate the efficiency of the approach and its relevance for applications.

Transmission, trapping and filtering of waves in periodically constrained elastic plates

2011 ◽  
Vol 468 (2137) ◽  
pp. 76-93 ◽  
Author(s):  
S. G. Haslinger ◽  
N. V. Movchan ◽  
A. B. Movchan ◽  
R. C. McPhedran
Keyword(s):  
Plane Waves ◽  
Elastic Plates ◽  
Flexural Waves ◽  
Quality Factors ◽  
Reflection And Transmission ◽  
Recurrence Algorithm ◽  
Transmission Resonances ◽  
Scattered Fields ◽  
Induced Transparency ◽  
Suppression Region

The paper discusses properties of flexural waves in elastic plates constrained periodically by rigid pins. A structured interface consists of rigid pin platonic gratings parallel to each other. Although the gratings have the same periodicity, relative shifts in horizontal and vertical directions are allowed. We develop a recurrence algorithm for constructing reflection and transmission matrices required to characterize the filtering of plane waves by the structured interface with shifted gratings. The representations of scattered fields contain both propagating and evanescent terms. Special attention is given to the analysis of trapped modes which may exist within the system of rigid pin gratings. Analytical findings are accompanied by numerical examples for systems of two and three gratings. We show geometries containing three gratings in which transmission resonances have very high quality factors (around 35 000). We also show that controlled lateral shifts of three gratings can give rise to a transmission peak with a sharp central suppression region, akin to the phenomenon of electromagnetic-induced transparency.

scholarly journals Cosserat Elastoplastic Finite Elements for Masonry Structures

2014 ◽  
Vol 624 ◽  
pp. 131-138 ◽  
Author(s):  
Michele Godio ◽  
Ioannis Stefanou ◽  
Karam Sab ◽  
Jean Sulem
Keyword(s):  
Finite Elements ◽  
Projection Algorithm ◽  
Elastic Plates ◽  
Discrete Elements ◽  
Backward Euler ◽  
Out Of Plane ◽  
Evolution Laws ◽  
Definition Of ◽  
Closest Point Projection ◽  
Point Projection

A Finite Elements formulation previously developed for Cosserat elastic plates, has been extended herein to the elastoplastic framework. Material non-linearities are taken into account through the implementation of a backward-Euler closest-point-projection algorithm, for which the definition of non-smooth yield loci and non-associated plastic potentials and evolution laws is made possible. An existing homogenized elastic constitutive model and a set of yield criteria for the out-of-plane behaviour of block-masonry are implemented in the code and their validity is discussed based on the comparison with Discrete Elements simulations. The comparison is carried out in both the static and the dynamic regime.

In-plane and out-of-plane waves in nanoplates immersed in bidirectional magnetic fields

2017 ◽  
Vol 61 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Keivan Kiani ◽  
Saeed Asil Gharebaghi ◽  
Bahman Mehri
Keyword(s):  
Magnetic Fields ◽  
Plane Waves ◽  
Out Of Plane
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