• Title/Summary/Keyword: Phononic crystal

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Acoustic Band Structures in Two-dimensional Phononic Crystals with a Square Lattice in Water (수중에서 정방형 격자를 갖는 2차원 포노닉 크리스탈의 음향 밴드 구조)

  • Kim, Yoon Mi;Lee, Kang Il;Kang, Hwi Suk;Yoon, Suk Wang
    • The Journal of the Acoustical Society of Korea
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    • v.34 no.5
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    • pp.335-342
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    • 2015

  • Phononic crystals are composite materials consisting of a periodic arrangement of scattering inclusions in a host material. One of the most important properties of phononic crystals is the existence of band gaps, i.e., ranges of frequencies at which acoustic waves cannot propagate through the structure. The present study aims to investigate theoretically and experimentally the acoustic band structures in two-dimensional (2D) phononic crystals consisting of periodic square arrays of stainless steel solid cylinders with a diameter of 1 mm and a lattice constant of 1.5 mm in water. The theoretical dispersion relation that depicts the relationship between the frequency and the wave vector was calculated along the ${\Gamma}X$ direction of the first Brillouin zone using the finite element method to predict the band structures in the 2D phononic crystals. The transmission and the reflection coefficients were measured in the 2D phononic crystals with 1, 3, 5, 7, and 9 layers of stainless steel cylinders stacked in the perpendicular direction to propagation at normal incidence. The theoretical dispersion relation exhibited five band gaps at frequencies below 2 MHz, the first gap appearing around a frequency of 0.5 MHz. The location and the width of the band gaps experimentally observed in the transmission and the reflection coefficients appeared to coincide well with those determined from the theoretical dispersion relation.

  • https://doi.org/10.7776/ASK.2015.34.5.335 인용 PDF KSCI

Finite Element Modeling for the Analysis of In- and Out-of-plane Bulk Elastic Wave Propagation in Piezoelectric Band Gap Structures (압전 밴드 갭 구조물의 면내·외 방향 체적 탄성파 전파 특성 해석을 위한 유한요소 모델링)

  • Kim, Jae-Eun;Kim, Yoon-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.8
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    • pp.957-964
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    • 2011

  • This investigation presents a finite element method to obtain the transmission properties of bulk elastic waves in piezoelectric band gap structures(phonon crystals) for varying frequencies and modes. To this end, periodic boundary conditions are imposed on a three-dimensional model while both in-plane and out-of-plane modes are included. In particular, the mode decoupling characteristics between in-plane and out-of-plane modes are identified for each electric poling direction and the results are incorporated in the finite element modeling. Through numerical simulations, the proposed modeling method was found to be a useful, effective one for analyzing the wave characteristics of various types of piezoelectric phononic band gap structures.

  • https://doi.org/10.3795/KSME-A.2011.35.8.957 인용 PDF KSCI