نتائج البحث - "wave propagation"

1

Review of exploiting nonlinearity in phononic materials to enable nonlinear wave responses

المؤلفون: Ganesh U. Patil, Kathryn H. Matlack

المصدر: Acta Mechanica. 233:1-46

مصطلحات موضوعية: Nonlinear wave propagation, Nonlinear system, Field (physics), Computer science, Mechanical Engineering, Acoustics, Solid mechanics, Computational Mechanics, Metamaterial, Boundary value problem, Mechanical wave, Material properties

الوصف: Phononic materials are periodically arranged building blocks in the form of material properties, geometries, and/or boundary conditions. This synthetic architecture makes phononic materials capable of manipulating mechanical waves that have potential applications across multiple disciplines of physics and engineering. Initial studies have been focused on linear phononic materials that assume small-amplitude waves. The incorporation of nonlinearity, however, has been shown to open opportunities for a new realm of dynamic responses valid beyond the small-amplitude regime. Acknowledging this potential, research in the field has undergone a paradigm shift in the last decade or so by exploiting various sources of nonlinearities within phononic materials. A comprehensive overview of the origin of nonlinearities and how they are modeled, solved, and realized in phononic materials, and specifically, what role nonlinearity plays in enabling rich nonlinear wave responses, is crucial for the future advancement of the field. In this review, we discuss recent advances in nonlinear wave propagation in phononic materials and metamaterials by drawing links between different phononic media and their nonlinearity-induced behaviors. We first briefly discuss the analytical methods employed to solve nonlinear wave propagation problems by focusing on foundational models. We then review physics-based sources of nonlinearities, primarily, material, geometric, and contact nonlinearities and elucidate nonlinear wave responses enabled by them in phononic materials and metamaterials. Finally, we outline existing challenges and possible future directions in nonlinear phononics and metamaterials.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::be130a5883082d7da3c50f1d9e81347dTest
https://doi.org/10.1007/s00707-021-03089-zTest

2

A Study of Longitudinal Waveguide with Band Gap Using Cylindrical and Conical Shape Periodic Structure

المؤلفون: Dong Hyeon Oh, Gil Ho Yoon

المصدر: Applied Sciences; Volume 11; Issue 16; Pages: 7257
Applied Sciences, Vol 11, Iss 7257, p 7257 (2021)

الوصف: This research presents the theoretical and experimental studies for cylindrical and conical periodic structures to control longitudinal wave motion. Many relevant researches exist to stop and pass a certain frequency wave without active devices with periodic structures called metamaterials. To modify or control longitudinal wave propagation, i.e., passing or blocking mechanical wave within specific frequency ranges, repeated mass-spring systems or metamaterials can be applied. By integrating a few identical structural components to form a whole structure, it is possible to make a mechanical filter for wave propagation. Most studies rely on straight bar with cylindrical structure. Thus, with a unit cell that have a cylindrical and conical structure, this research presents the extensions toward the studies of the wave motions for straight and curved bars with finite element simulations and experiment studies. The results show that the hybrid cylindrical and conical periodic structures can be effective in terms of wave motion control and stiffness.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fd30367672c6257311eccc999ceb0e0cTest

3

Passive-adaptive mechanical wave manipulation using nonlinear metamaterial plates

المؤلفون: James M. Manimala, T. A. Emerson

المصدر: Acta Mechanica. 231:4665-4681

الوصف: In many controlled acoustics applications, it is desirable to engineer passive-adaptive manipulation of mechanical waves through waveguides based solely on varying dynamic input. We investigate the potential of achieving this using experiments on several types of nonlinear acoustic metamaterial plates. By tuning the amplitude-dependent response of locally resonant attachments and tailoring their patterning on or within a host plate-type medium, amplitude-activated shifts in bandgap frequency ranges could be utilized to tailor the direction and bandwidth of wave propagation through such metamaterials. Prototype test articles for passive-adaptive wave rejection, steering, sorting and selective beaming were constructed and tested using customized rigs. The location, extent and shift of bandgaps were experimentally and numerically verified. Scalable waveguide designs are experimentally evaluated for low (150–250 Hz) and much higher (16–20 kHz) frequency ranges. The potential to steer and sort waves in a tunable frequency range toward specific regions or paths within the waveguide is demonstrated. With current precision and hybrid fabrication techniques attaining commercial maturity, metamaterials-based approaches offer great promise in realizing waveguides with built-in, adaptive functionalities related to filtering, transduction and actuation for mechanical waves.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::b5c2f98cc46025486a0753b811fb7457Test
https://doi.org/10.1007/s00707-020-02782-9Test

4

SPECFEM2D-DG, an open-source software modelling mechanical waves in coupled solid-fluid systems: the linearized Navier-Stokes approach

المؤلفون: Raphaël F. Garcia, L. Martire, Quentin Brissaud, Roland Martin

المساهمون: Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

المصدر: Geophysical Journal International
Geophysical Journal International, 2022, 228, pp.664-697. ⟨10.1093/gji/ggab308⟩

مصطلحات موضوعية: Interface waves, Wave propagation, Infrasound, Numerical modelling, Computational seismology, Physics::Medical Physics, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Open source software, Mechanics, Geophysics, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Navier stokes, Mechanical wave, Geology

الوصف: SUMMARYWe introduce SPECFEM2D-DG, an open-source, time-domain, hybrid Galerkin software modelling the propagation of seismic and acoustic waves in coupled solid–fluid systems. For the solid part, the visco-elastic system from the routinely used SPECFEM2D software is used to simulate linear seismic waves subject to attenuation. For the fluid part, SPECFEM2D-DG includes two extensions to the acoustic part of SPECFEM2D, both relying on the Navier–Stokes equations to model high-frequency acoustics, infrasound and gravity waves in complex atmospheres. The first fluid extension, SPECFEM2D-DG-FNS, was introduced in 2017 by Brissaud, Martin, Garcia, and Komatitsch; it features a nonlinear Full Navier–Stokes (FNS) approach discretized with a discontinuous Galerkin numerical scheme. In this contribution, we focus only on introducing a second fluid extension, SPECFEM2D-DG-LNS, based on the same numerical method but rather relying on the Linear Navier–Stokes (LNS) equations. The three main modules of SPECFEM2D-DG all use the spectral element method (SEM). For both fluid extensions (FNS and LNS), two-way mechanical coupling conditions preserve the Riemann problem solution at the fluid–solid interface. Absorbing outer boundary conditions (ABCs) derived from the perfectly matched layers’ approach is proposed for the LNS extension. The SEM approach supports complex topographies and unstructured meshes. The LNS equations allow the use of range-dependent atmospheric models, known to be crucial for the propagation of infrasound at regional scales. The LNS extension is verified using the method of manufactured solutions, and convergence is numerically characterized. The mechanical coupling conditions at the fluid–solid interface (between the LNS and elastodynamics systems of equations) are verified against theoretical reflection-transmission coefficients. The ABCs in the LNS extension are tested and prove to yield satisfactory energy dissipation. In an example case study, we model infrasonic waves caused by quakes occurring under various topographies; we characterize the acoustic scattering conditions as well as the apparent acoustic radiation pattern. Finally, we discuss the example case and conclude by describing the capabilities of this software. SPECFEM2D-DG is open-source and is freely available online on GitHub.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::53ba078e84bbd8a013d12ccc360fe622Test
https://hal-insu.archives-ouvertes.fr/insu-03619992Test

5

Stochastic Model for Energy Propagation in Disordered Granular Chains

المؤلفون: Kianoosh Taghizadeh, Rohit Kumar Shrivastava, Stefan Luding

المساهمون: Multi Scale Mechanics, MESA+ Institute

المصدر: Materials
Volume 14
Issue 7
Materials, 14(7):1815. MDPI
Materials, Vol 14, Iss 1815, p 1815 (2021)

مصطلحات موضوعية: UT-Gold-D, Wave propagation, Stochastic modelling, Degrees of freedom (physics and chemistry), wave propagation, master equation, lcsh:Technology, 01 natural sciences, Article, 010305 fluids & plasmas, Momentum, 0103 physical sciences, Master equation, Wavenumber, General Materials Science, Statistical physics, lcsh:Microscopy, 010306 general physics, stochastic model, lcsh:QC120-168.85, Physics, lcsh:QH201-278.5, lcsh:T, 1D granular chain, disorder, 621.3, Mean field theory, lcsh:TA1-2040, lcsh:Descriptive and experimental mechanics, lcsh:Electrical engineering. Electronics. Nuclear engineering, lcsh:Engineering (General). Civil engineering (General), Mechanical wave, lcsh:TK1-9971

الوصف: Energy transfer is one of the essentials of mechanical wave propagation (along with momentum transport). Here, it is studied in disordered one-dimensional model systems mimicking force-chains in real systems. The pre-stressed random masses (other types of disorder lead to qualitatively similar behavior) interact through (linearized) Hertzian repulsive forces, which allows solving the deterministic problem analytically. The main goal, a simpler, faster stochastic model for energy propagation, is presented in the second part, after the basic equations are re-visited and the phenomenology of pulse propagation in disordered granular chains is reviewed. First, the propagation of energy in space is studied. With increasing disorder (quantified by the standard deviation of the random mass distribution), the attenuation of pulsed signals increases, transiting from ballistic propagation (in ordered systems) towards diffusive-like characteristics, due to energy localization at the source. Second, the evolution of energy in time by transfer across wavenumbers is examined, using the standing wave initial conditions of all wavenumbers. Again, the decay of energy (both the rate and amount) increases with disorder, as well as with the wavenumber. The dispersive ballistic transport in ordered systems transits to low-pass filtering, due to disorder, where localization of energy occurs at the lowest masses in the chain. Instead of dealing with the too many degrees of freedom or only with the lowest of all the many eigenmodes of the system, we propose a stochastic master equation approach with reduced complexity, where all frequencies/energies are grouped into bands. The mean field stochastic model, the matrix of energy-transfer probabilities between bands, is calibrated from the deterministic analytical solutions by ensemble averaging various band-to-band transfer situations for short times, as well as considering the basis energy levels (decaying with the wavenumber increasing) that are not transferred. Finally, the propagation of energy in the wavenumber space at transient times validates the stochastic model, suggesting applications in wave analysis for non-destructive testing, underground resource exploration, etc.
Deutsche Forschungsgemeinschaft
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
European-Union Marie Curie Initial Training Network, T-MAPPP

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ee68cea63760e329a56668a0e0e5af1cTest
http://europepmc.org/articles/PMC8038819Test

6

Ultrafast four-dimensional imaging of cardiac mechanical wave propagation with sparse optoacoustic sensing

المؤلفون: Michael Reiss, Xosé Luís Deán-Ben, Ali Ozbek, Daniel Razansky, Çağla Özsoy

المساهمون: University of Zurich, Razansky, Daniel

المصدر: Proc Natl Acad Sci U S A

الوصف: Propagation of electromechanical waves in excitable heart muscles follows complex spatiotemporal patterns holding the key to understanding life-threatening arrhythmias and other cardiac conditions. Accurate volumetric mapping of cardiac wave propagation is currently hampered by fast heart motion, particularly in small model organisms. Here we demonstrate that ultrafast four-dimensional imaging of cardiac mechanical wave propagation in entire beating murine heart can be accomplished by sparse optoacoustic sensing with high contrast, ∼115-µm spatial and submillisecond temporal resolution. We extract accurate dispersion and phase velocity maps of the cardiac waves and reveal vortex-like patterns associated with mechanical phase singularities that occur during arrhythmic events induced via burst ventricular electric stimulation. The newly introduced cardiac mapping approach is a bold step toward deciphering the complex mechanisms underlying cardiac arrhythmias and enabling precise therapeutic interventions.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::11a580ca30da5b20ab9b645d5cef2cafTest
https://doi.org/10.5167/uzh-216022Test

7

Valley-dependent topologically protected elastic waves using continuous graphene membranes on patterned substrates

المؤلفون: Jaehyung Hong, Joo Hwan Oh, Sung Youb Kim, Harold S. Park

المصدر: Nanoscale. 12:8997-9004

مصطلحات موضوعية: Materials science, Condensed matter physics, Graphene, Wave propagation, 02 engineering and technology, Substrate (electronics), 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, Membrane, Lattice constant, Hall effect, law, 0103 physical sciences, Nano, General Materials Science, 010306 general physics, 0210 nano-technology, Mechanical wave

الوصف: We present a novel structure for topologically protected propagation of mechanical waves in a continuous, elastic membrane using an analog of the quantum valley Hall effect. Our system involves a thin, continuous graphene monolayer lying on a pre-patterned substrate, and as such, it can be employed across multiple length scales ranging from the nano to macroscales. This enables it to support topologically-protected waves at frequencies that can be tuned from the kHz to GHz range by either selective pre-tensioning of the overlaying membrane, or by increasing the lattice parameter of the underlying substrate. We show through numerical simulations that this continuous system is robust against imperfections, is immune to backscattering losses, and supports topologically-protected wave propagation along all available paths and angles. We demonstrate the ability to support topologically-protected interface modes using monolayer graphene, which does not intrinsically support topologically non-trivial elastic waves.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::41520c2b71ecbc1ec4011bad7453cef9Test
https://doi.org/10.1039/c9nr09809gTest

8

Design and analysis of a soft shell array supporting variable velocity propagation of mechanical waves

المؤلفون: Peng Yan, Pengbo Liu, Xiaoyuan Ma

المصدر: 2021 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO).

مصطلحات موضوعية: Physics, Wave propagation, Acoustics, Logic gate, Shell (structure), Actuator, Mechanical wave, Characteristic energy, Spherical shell, Finite element method

الوصف: Mechanical waves have a wide range of applications in autonomous soft devices such as mechanical logic gates and microrobots. However, the wave velocity is constant in most systems driven by mechanical waves. This significantly limits the application of mechanical waves in some systems (e.g., soft robots capable of sequence control) that possess a spatial distribution of the heterogeneous energy. In this study, a soft spherical shell array composed of soft-shell elements connected by linear springs is proposed to achieve an adjustable wave velocity. Specifically, the effect of the geometric parameters of a single shell on the energy characteristics is quantified by Finite Element simulations. Theoretical and numerical analyses of the wave properties are also provided. Their results show that adjustable wave propagation behaviors can be designed using the geometrical parameters of the elements. This study provides a basis for the design of energy-efficient soft devices such as soft actuators, controllable energy absorbers and shape-morphing systems.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::eb820a0fbeb9862fda8770713686ed79Test
https://doi.org/10.1109/3m-nano49087.2021.9599781Test

9

In vivo elasticity mapping in human skin with AuT-based OCE

المؤلفون: Ruikang K. Wang, Peijun Tang, Hong-Cin Liou, Matthew O'Donnell, Russell Ettiger, Ivan Pelivanov, John J. Pitre, Mitchell A. Kirby, Samuel P. Mandell

المصدر: Optical Elastography and Tissue Biomechanics VIII.

مصطلحات موضوعية: Materials science, integumentary system, medicine.diagnostic_test, Wave propagation, Quantitative Biology::Tissues and Organs, Physics::Medical Physics, Mathematical analysis, Isotropy, Human skin, Elasticity (physics), Moduli, medicine, Elastography, Anisotropy, Mechanical wave

الوصف: Using numerical and analytical models of wave propagation in mechanically anisotropic materials, we highlight the complications associated with quantitative estimates of mechanical moduli in human skin. To obtain reliable, quantitative measurements of moduli in human skin, multiple aspects of mechanical wave propagation in structures typical of skin must be considered. Using a nearly incompressible transverse isotropic (NITI) model, preliminary measurements of both shear moduli (G and μ) in healthy in vivo human skin are presented.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::ca843f75644ec6b103fa473354e5be52Test
https://doi.org/10.1117/12.2577044Test

10

Nano-pumping of fullerene and water molecules via a carbon nanotube in vacuum and aqueous environments

المؤلفون: Mehran Shahryari, Akbar Nazari-Golshan, S. Salman Nourazar

المصدر: The European Physical Journal Plus. 136

الوصف: Nano-pumping of molecules via a carbon nanotube (CNT) can be achieved by mechanical actuation and wave propagation through the tube wall which is generated by two oscillating tips. By using non-equilibrium molecular dynamics (NEMD) simulations, we investigate the effects of tip frequency and amplitude in the pumping of a C20 molecule through (13, 0) CNT in the vacuum environment. The pumping action (C20 ejection) does not succeed in all tip frequencies and amplitudes, and there are optimum points in which successful pumping takes place. In one of these successful pumping conditions (specific tip frequency and amplitude), we have performed NEMD simulations of water and fullerene pumping in an aqueous environment and found that mechanical wave propagation is much weaker in such an environment and the pumping of C20 molecule does not succeed. Our simulations show that mechanical wave velocity along CNT can reach as a high as 5000 m/s. And during the pumping process, the C20 molecule accelerates due to transferring kinetic energy and the velocity remains constant since no external force is applied on C20 molecule.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::ccde83d4007857d89a29fcc49c41249eTest
https://doi.org/10.1140/epjp/s13360-021-01137-0Test

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