Browsing by Subject "Phononic crystal"

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Open Access
Observation of elastic Weyl points in ferroelectric basedsonic metamaterials
(Taylor & Francis Inc., 2024-02-20) Özer, Zafer; Palaz, Selami; Mamedov, Amirullah M.; Özbay, Ekmel
The study of Weyl points in electronic systems has recently inspired extensive research in classical systems, such as photonic and acoustic lattices. We construct a single-phase three-dimensional structure, an analog of the honeycomb lattice, and then predict the existence of Weyl points with opposite topological charges (±1) as well as the associated gapless topologically protected surface states. We apply full-scale numerical simulations on the elastic three-dimensional structure and present a clear visualization of the topological surface states that are directional and robust. Such designed lattices can pave the way for novel vibration control and energy harvesting on structures that are ubiquitous in many engineering applications.
Open Access
Phononic band gap and wave propagation on multiferroic-based acoustic metamaterials
(Taylor & Francis, 2019) Palaz, S.; Oltulu, O.; Özer, Z.; Mamedov, Amirullah M.; Özbay, Ekmel
In the present work, the acoustic band structure of a two-dimensional (2D) phononic crystal containing a multiferroic and liquid were investigated by the plane-wave-expansion method. 2D PnC with triangular and honeycomb lattices composed of LiCu2O4 cylindrical rods embedded in the seawater matrix are studied to find the existence of stop bands for the waves of certain energy. Phononic band diagram ω=ω(k) for a 2D PC, in which nondimensional frequencies ωa/2πc (c-velocity of wave) were plotted versus the wavevector k along the г-X-M-г path in the Brillouin zone show few stop bands in the frequency range between 10 and 110 kHz.
Open Access
Phononic crystals with archimedean-like tiling: band structure and the transformation of sound
(Taylor & Francis, 2021-12-01) Ozer, Z.; Mamedov, Amirullah M.; Ozbay, Ekmel
In this study, we investigate acoustic wave propagation in 3 D phononic crystal (PnC) slabs wherein scatterers have different cross sections by using the finite-element method. The PnC consists of scatterers embedded in the host material arranged in a square lattice and honeycomb lattice in different patterns (bathroom and ladybug tiling in Archimedean-like tiling). By determining the eigenmodes and band gaps, complete and accurate band structures and transmission spectra are obtained. Compared to traditional square lattice PnCs, it has been observed that the bands obtained in pattern structures may have some advantages in terms of width and position. It was also shown that the low-frequency response of two Archimedean-like structures was similar with respect to the traditional square lattice.