Optimal Designs of Phononic Crystal Microstructures Considering Point and Line Defects

He, Jingjie; Sun, Jiamei; Fan, Juncheng; Jia, Zhiyuan; Zhang, Xiaopeng

doi:10.3390/sym13111993

Cited by 3 publications

(1 citation statement)

References 57 publications

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“…The above results are beneficial to the manufacture of acoustic filters and waveguides with adjustable frequency bands. For optimal design, a two-stage optimization strategy has been developed to design defective PnC to examine the localization of target frequency and waveguide state, 18 so the optimal design can be achieved by changing the design parameters. Zhang 19 created three novel arrays to expand the BG of local resonance, which formed a WG and might be more suitable for noise reduction of railway or highway vehicles compared with the conventional PnC plate.…”

Section: Introductionmentioning

confidence: 99%

Band Gap and Waveguide Characteristics of Petal-Shaped Scatterer Phononic Crystals

Li¹,

Xiang²,

Wang³

et al. 2023

The International Journal of Acoustics and Vibration

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In this study, the Bragg petal-shaped scatterer (PS) phononic crystal (PnC) model is built to expand the width of band gap (BG). The BG characteristics of the PSPnC, square, circular, octagonal, and the "+" shaped scatterer PnC are compared using the finite element method (FEM). This study investigates the effects of the internal and external diameter ratio and the number of petals of single-layer petals, double-layer petals and the application of pre-deformation without changing their structure on the BG characteristics of PnCs for the transmission characteristics of supercell structures. Moreover, two different waveguides (WGs) are built with pre-deformed unit cells as the defects. As revealed by the results, the PSPnC exhibited better vibration isolation performance than PnCs with other shapes. More BGs will appear at a higher frequency with the decrease in the ratio of inner and outer diameter of petals and the increase in the number of petals. In addition, the double-layer PSPnC has high performance, and the dislocation arrangement of PS can enhance the vibration isolation performance of PSPnC. Furthermore, the WG structure is capable of guiding the energy, which provides a new insight into the establishment of the filter.

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Section: Introductionmentioning

confidence: 99%

Band Gap and Waveguide Characteristics of Petal-Shaped Scatterer Phononic Crystals

Li¹,

Xiang²,

Wang³

et al. 2023

The International Journal of Acoustics and Vibration

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Tunable bandpass filters using a defective phononic crystal shunted to synthetic negative capacitance for longitudinal waves

Jo,

Park,

Kim

et al. 2024

Journal of Applied Physics

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This study illustrates the successful achievement of tunable defect bands in one-dimensional defective phononic crystals (PnCs) through the incorporation of piezoelectric defects with synthetic negative capacitances (SNCs) for the first time. The efficacy of SNCs in creating tunable bandpass filters across a broad frequency range is thoroughly examined using the proposed analytical and numerical models. A newly developed electroelastically coupled transfer matrix that incorporates SNCs is presented, considering either series or parallel connection between bimorph piezoelectric elements. Defect band and transmittance analyses are conducted using the transfer matrix and S-parameter methods. Two key findings emerge from this investigation. First, when the total equivalent capacitance of the bimorph piezoelectric elements and SNC becomes zero, the defect band representing the point-symmetric defect-mode shape can be customized throughout the entire phononic bandgap. Second, the constant transmittance value, resembling short-circuit conditions, highlights the remarkable ability of SNCs to tune defect bands without energy dissipation, paving the way for fully tunable bandpass filters. To propel this research forward, future investigations could explore expanding the design space with double defects, adopting enhanced modeling techniques to account for lateral and shear effects, developing a control algorithm for the automatic optimization of SNC values in actively tunable bandpass filters, and incorporating artificial intelligence into design methods for piezoelectric defects with electrical connections.

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Experimental Validation for Mechanically Tunable Defect Bands of a Reconfigurable Phononic Crystal with Permanent Magnets

Yang,

2024

Crystals

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Phononic crystals (PnCs) have garnered significant attention due to their unique ability to control elastic waves in unconventional ways. One area of research focuses on utilizing defects within PnCs. Defects create new pass bands within band gaps, leading to concentrated wave energy within the defects. However, defect-mode-enabled wave localization is effective only at specific frequencies, limiting its usefulness when the frequencies of incident waves vary. Existing methods to mechanically tune defect bands involve changing the geometries of unit cells or defects or attaching elastic foundations, which necessitates the detachment and reattachment of certain structures depending on the engineering situation. Considering these challenges, this study introduces a novel approach that utilizes the reconfigurable PnC design, incorporating permanent magnets and ferromagnetic materials. The case study involves a one-dimensional PnC consisting of a long metal beam with rectangular block-shaped permanent magnets periodically arranged and attached to the beam by magnetic forces. A defect is created by shifting a subset of these block-shaped permanent magnets in parallel. The extent of this parallel movement alters the vibrating characteristics of the defect, facilitating the mechanical control of the defect bands in the defective PnC. The effectiveness of this approach is experimentally validated.

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Optimal Designs of Phononic Crystal Microstructures Considering Point and Line Defects

Cited by 3 publications

References 57 publications

Band Gap and Waveguide Characteristics of Petal-Shaped Scatterer Phononic Crystals

Band Gap and Waveguide Characteristics of Petal-Shaped Scatterer Phononic Crystals

Tunable bandpass filters using a defective phononic crystal shunted to synthetic negative capacitance for longitudinal waves

Experimental Validation for Mechanically Tunable Defect Bands of a Reconfigurable Phononic Crystal with Permanent Magnets

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