Figure 4 - available via license: Creative Commons Attribution 4.0 International
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Displacement fields for the four-inclusion waveguide mode consisting of 3 µm deep inclusions (175.40 MHz). The color scale shows the local displacement of the waveguide mode along the (a) x-, (b) y-and (c) z-directions. Scale: microns.
Source publication
A phononic crystal waveguide is presented that consists of the inverse of a typical structure. Instead of a defect waveguide within an extended phononic crystal, this waveguide consists of a phononic crystal of finite width, and the phononic crystal itself is composed of a shallow array of holes. The acoustic velocity is actually reduced in the pho...
Contexts in source publication
Context 1
... examine the waveguide mode more closely, the components of the real displacements u x , u y and u z are shown in Figure 4. The sagittal displacement components in the xz-plane are well confined to the waveguide, which is expected given the requirements of the polarization and core strain energy ratios. ...
Context 2
... y-displacement component seems to be accommodating strain from the sagittal waveguide mode. For the given phase of the waveguide mode propagation in Figure 4, the z-displacement is into the bulk, and both the x-and y-displacements are compressing the inclusions at the surface in a type of breathing mode. For the material below the inclusions, the negative z-displacement compresses the bulk with the strain being accommodated by lateral shear outwards from the waveguide. ...
Citations
Phononic crystals are renowned for their distinctive wave propagation characteristics, notably bandgaps that offer precise control over vibration phenomena, positioning them as a critical material in advanced vibro-elastic engineering and design. We investigate how pore shapes influence the bandgap in continuum two-dimensional phononic crystals made from a single material. Using the square lattice and unit cells with fourfold symmetry, our numerical analyses reveal that the normalized gap size is highly dependent on the minimum ligament width in the structure. Additionally, we find that fine geometric features represented by higher-order Fourier coefficients decrease the gap size. This study offers insight into the design of phononic crystals and vibro-elastic metamaterials for precise wave control through void patterning.
