共查询到20条相似文献,搜索用时 31 毫秒
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设计了在镍圆柱体底部添加薄环氧树脂并沉积在铌酸锂基底的二维复合压电型声子晶体。通过有限元法计算了该结构的能带结构、分析了其带隙特性。计算结果显示:通过引入环氧树脂来减小散射体的有效弹性模量,从而降低了声表面波(SAW)完全带隙,同时打开了多条SAW方向带隙。计算了传输损失来验证带隙的存在性且讨论了其传输特性。利用布里渊区高对称点X处不同本征模态的位移场分析了带隙的形成机理。此外,还研究了共振体几何参数对SAW完全带隙、XM方向SAW带隙特性的影响,研究发现,随环氧树脂厚度的增加,在XM方向出现了一条宽为158 MHz的宽禁带。研究结果为设计基于声子晶体的电声设备提供了参考。 相似文献
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The band gaps of a laminated piezoelectric/piezomagnetic phononic crystal with graded interlayer are studied in this paper. First, the transfer matrix method and the Bloch theorem are used to derive the dispersion equation. Next, the graded interlayer with different gradient profiles between the piezoelectric and the piezomagnetic materials is considered. The graded interlayer is modeled as a system of homogenous sublayers with both piezoelectric and piezomagnetic effects simultaneously. The effect of the graded interlayer on the band gap is introduced by inserting an additional interlayer transfer matrix in the calculation of the total transfer matrix. Finally, the dispersion equation is solved numerically, and the dispersive curves are shown in the Brillouin zone. The band gaps of the phononic crystal with graded interlayer are compared with that without graded interlayer. The influences of the graded interlayer with different gradient profiles on the band gap of a laminated piezoelectric/piezomagnetic phononic crystal are discussed based on the numerical results. 相似文献
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声子晶体能够产生完全的弹性波禁带,可以阻止声波或者振动在其内部传播。采用平面波算法研究了二维正方点阵声子晶体的禁带结构。在甲醇/水银双组分二维(2D)液相体系中发现了很大的完全禁带,到目前为止,在固相体系和其他液相体系中还没有发现相同宽度和相同数量的完全禁带。还研究了声子晶体中散射体的横截面为圆形和绕其中心轴旋转任意角度的正方形时完全禁带的产生规律,探索了第一禁带宽度与第一禁带中心频率的比值△Ω1/Ωc1和填充率F之间的关系,以及前50个频带中禁带的总宽度∑△Ωn/Ωcn和填充率F之间的关系。 相似文献
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The band gap of one dimensional (1D) phononic crystal with viscoelastic host material is studied in this paper. The standard solid model is used to simulate the viscoelastic behavior of the host material and the fillers embedded in the host material are still assumed elastic material. The band gap problem in 1D phononic crystal leads to an eigenvalue problem by using the plane wave expansion method and the Bloch–Floquet wave theory in a periodic structure. An iterative algorithm is designed to obtain the band gap structure due to the dependence of elastic constants on frequency for the viscoelastic host material. A numerical example is given for steel/epoxy phononic crystal. The band gap of 1D phononic crystal is evaluated for different viscoelastic constants, namely, relaxation time, initial and final state elastic modulus. It is found that the viscoelastic constants of host material affect not only the location but also the width of band gaps. 相似文献
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Hsu JC Wu TT 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(2):431-441
Based on Mindlin's piezoelectric plate theory and the plane wave expansion method, a formulation is proposed to study the frequency band gaps and dispersion relations of the lower-order Lamb waves in two-dimensional piezoelectric phononic plates. The method is applied to analyze the phononic plates composed of solid-solid and airsolid constituents with square and triangular lattices, respectively. Factors that influence the opening and width of the complete Lamb wave gaps are identified and discussed. For solid/solid phononic plates, it is suggested that the filling material be chosen with larger mass density, proper stiffness, and weak anisotropic factor embedded in a soft matrix in order to obtain wider complete band gaps of the lower-order Lamb waves. By comparing to the calculated results without considering the piezoelectricity, the influences of piezoelectric effect on Lamb waves are analyzed as well. On the other hand, for air/solid phononic plates, a background material itself with proper anisotropy and a high filling fraction of air may favor the opening of the complete Lamb wave gaps. 相似文献
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利用一维固-流结构矩形声子晶体中弹性波横向受限的条件,推导出弹性波在其中各个模式满足的关系式,利用它研究了弹性波各模式的特性。并利用色散法研究了弹性波的传输特性随模式量子数和矩形边长的变化规律。得出了一些不同于一维非受限声子晶体的新特征,即一维矩形声子晶体的禁带由模式量子数确定,禁带频率中心和频率宽度与模式量子数和边长有关。 相似文献
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Hsieh PF Wu TT Sun JH 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(1):148-158
This paper aims at studying the band gap phenomena of three-dimensional phononic crystals using the finite difference time domain (FDTD) method and a PC cluster system. In the paper, Bloch's theorem is applied to the wave equation and to the boundary conditions of the periodic structure. We calculate the variations of displacements and take discrete Fourier transform to acquire the resonances of the structures. Then, the dispersion relations of the bulk acoustic wave can be obtained and the band gaps are predicted accordingly. On the other hand, because of larger data calculation in three-dimensional phononic crystals, we introduce the PC cluster system and parallel FDTD programs written with respect to the architecture of a PC cluster system. Finally, we discuss the numerical calculation of two-dimensional and three-dimensional phononic crystals consisting of steel/epoxy and draw conclusions regarding the band gap phenomena between these phononic crystals. 相似文献
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A local RBF collocation method for band structure computations of 2D solid/fluid and fluid/solid phononic crystals 下载免费PDF全文
Hui Zheng Chuanzeng Zhang Yuesheng Wang Wen Chen Jan Sladek Vladimir Sladek 《International journal for numerical methods in engineering》2017,110(5):467-500
In this paper, an efficient local radial basis function collocation method (LRBFCM) is presented for computing the band structures of the two‐dimensional (2D) solid/fluid and fluid/solid phononic crystals. Both systems of solid scatterers embedded in a fluid matrix (solid/fluid phononic crystals) and fluid scatterers embedded in a solid matrix (fluid/solid phononic crystals) are investigated. The solid–fluid interactions are taken into account by properly formulating and treating the continuity/equilibrium conditions on the solid–fluid interfaces, which require an accurate computation of the normal derivatives of the displacements and the pressure on the fluid–solid interfaces and the unit‐cell boundaries. The developed LRBFCM for the mixed wave propagation problems in 2D solid/fluid and fluid/solid phononic crystals is validated by the corresponding results obtained by the finite element method (FEM). To the best knowledge of the authors, the present LRBFCM has yet not been applied to the band structure computations of 2D solid/fluid and fluid/solid phononic crystals. For different lattice forms, scatterers' shapes, acoustic impedance ratios, and material combinations (solid scatterers in fluid matrix or fluid scatterers in solid matrix), numerical results are presented and discussed to reveal the efficiency and the accuracy of the developed LRBFCM for calculating the band structures of 2D solid/fluid and fluid/solid phononic crystals. A comparison of the present numerical results with that of the FEM shows that the present LRBFCM is much more efficient than the FEM for the band structure computations of the considered 2D solid/fluid and fluid/solid phononic crystals. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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设计了一种新型复合局域共振型声子晶体,通过建立弹簧-质量块等效模型用于计算带隙的上下边界频率,同时结合有限元方法分析了该结构共振带隙的产生机理,根据带隙起止点频率处的位移模态研究了声子晶体的带隙特性。研究结果表明,该声子晶体结构在频率2 200 Hz附近产生三条完整带隙,其中一条是带宽达406.17 Hz的宽带隙。对于有限周期结构的声子晶体进行了传输特性仿真和隔声实验测试,在相同的频段内弹性波传播受到了阻碍。最后,对影响声子晶体带隙打开的几种因素进行分析,讨论了带隙上下边界调控机制。研究结果为声子晶体获得较宽的低频带隙提供了一种新的设计思路和方法。 相似文献
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利用转移矩阵和离散方法研究了密度正弦变化的一维声子晶体中弹性波的禁带.研究声明,密度按正弦规律变化的一维声子晶体中的弹性波会出现禁带.禁带频率的宽度随密度幅值的增加而增大,但密度幅值的变化对主禁带的频率中心没有影响.禁带的频率宽度和频率中心都随周期厚度呈反比变化. 相似文献