Mathematical Physics, Applied Mathematics, Modeling and Simulation, Mechanics of Materials
7
Scopus Publications
Scopus Publications
Stochastic excitation method for calculating the resolvent band structure of periodic media and waveguides Vincent Laude, Maria E. Korotyaeva Physical Review B, 2018 We introduce a stochastic excitation method for calculating the dispersion relation for waves propagating in periodic media or along waveguides and subject to material loss or radiation damping. Instead of looking for an explicit or implicit functional relation between frequency ω and wave number k, as is usually done, we consider a mapping of the resolvent set in the dispersion space (ω,k). Bands appear as the trace of Lorentzian responses containing local information on propagation loss in both time and space domains. For illustration purposes, the method is applied to a lossy sonic crystal, a radiating surface phononic crystal, and a radiating optical waveguide. The resolvent band structure can be obtained for any system described by a time-harmonic wave equation.
Generation of coherent acoustic beams in solids by mixing of counterpropagating, detuned optical beams [Invited] Vincent Laude, Maria E. Korotyaeva, Jean-Charles Beugnot Applied Optics, 2018 We model the generation of coherent acoustic beams in a homogeneous solid from the interference of two oppositely propagating, detuned optical laser beams. This configuration is reciprocal to Brillouin light scattering in the backward interaction arrangement. Generation of a confined ultrasound beam is predicted, close to the Brillouin frequency. Optoacoustic gain spectra and beam shapes are obtained numerically using a finite element model. The acoustic spectra are non-symmetrical, i.e., non-Lorentzian, and result from excitation of the continuum of bulk elastic waves. The acoustic beam width correspondingly varies with detuning frequency and optical beam waist.
Surface acoustic wave-based characterization of randomly distributed surface cracks Roland Galos, István A. Veres, Saeid Zamiri, Maria Korotyaeva, Markus Wenin, Peter Burgholzer Physics Procedia, 2015 In this paper we present an approach to characterize surface breaking cracks by analayzing propagation of surface acoustic waves. We generate surface acoustic waves with plane wave fronts using a line-focused pulsed-laser to study scattering of SAWs on surface microcracks. A homogenized behavior of the randomly scattered and interferometrically detected field, i.e. the coherent waveform, is gained by spatially averaging the measurements. The data is studied in the time and frequency domain. The experimental results show the attenuation of the coherent SAWs due to scattering and the strongly distorted shape indicates the presence of dispersion. These parameters can be used to characterize the density and depth distribution of the cracks.
Resolvent method for calculating dispersion spectra of the shear waves in the phononic plates and waveguides M. E. Korotyaeva, A. A. Kutsenko, A. L. Shuvalov, O. Poncelet Journal of Computational Acoustics, 2014 We propose a new method for calculating dispersion spectra of shear waves in the two-dimensional free phononic plates made of solid matrix with periodically distributed inclusions and in the waveguides composed of a phononic layer between two periodic substrates. The method proceeds from the propagator M which involves exact integration in the depth coordinate. Because the components of M can be very large, the dispersion equation for a free plate is recast in terms of the resolvent of propagator R = (αI - M)-1 (α is a constant) which is numerically stable. The resolvent is the central object of the method. Another key tool, which comes into play in the case of a waveguide, is a projector P expressed as a contour integral of the resolvent of the substrate. The projector allows to extract the "physical" modes decreasing into the depth of the substrates without solving the wave equation. The resulting dispersion equation for a waveguide defined via the projectors for the substrates and the resolvent for the enclosed layer is numerically stable. We provide several options for the calculation of the resolvent and projector. Besides, special attention is given to derivation of the dispersion equations for the uncoupled symmetric and antisymmetric dispersion branches in the case of mirror-symmetric structures.
Love waves in two-dimensional phononic crystals with depth-dependent properties M. E. Korotyaeva, A. A. Kutsenko, A. L. Shuvalov, O. Poncelet Applied Physics Letters, 2013 We calculate subsonic spectra of the Love waves, i.e., of the shear horizontal waves in the coated substrate, using developed analytical approach. Coating or substrate or both are two-dimensional heterogeneous in the sagittal plane and uniform along the out-of-plane direction. Slow coating permits multiple subsonic dispersion branches which are folded due to lateral periodicity. It is observed that low-frequency branches may either cross or repulse each other, the latter giving rise to low-frequency band gaps inside the Brillouin zone. Such behavior is likelier when the periodic inclusion occurs within the coating close enough to its free surface.
