Quasi-Metamaterials: Quasicrystalline Mechnical Metamaterial Concepts for Advanced Engineering Application

EPSRC研究组合领域：连续介质力学（生长），结构力学（保持）描述：一种微结构准晶材料是由缺乏完美周期性的基本单元格组成的。准晶集合体是一种特殊的情况或更一般的准周期集合体。该团队最近在卡迪夫对一维准线性材料进行的研究表明，这些结构显示出与弹性波传播相关的特殊性质。特别是，这种波导的动态光谱（揭示了结构在给定频率下传输波的能力）具有缩放和自相似特性，可以用来设计能够屏蔽入射弹性波并减轻不必要振动的创新超材料。这些特征可以用一个优雅的数学理论来描述，该理论基于称为Kohmoto's invariant的不变函数的存在。该项目将侧重于将上述初步研究结果扩展到完全二维和三维框架，以便为基于准晶（QC）微观结构的创新超材料的有效设计提供指导。特别是，将追求以下里程碑：i）识别监督二维和三维QC材料动力学特性的不变量（第一年）; ii）研究QC材料的色散图及其缩放和自相似特性，作为一维结构中已知特性的扩展（第二年）; iii）研究原型装置，以评估不同频率的弹性波衰减（第三年）; iv）确定用于地震和MEMS工程中的工程应用的基于人造QC的超材料的设计准则（最后六个月）。

EPSRC Research Portfolio areas: Continuum mechanics (grow), Structural Mechanics (maintain)Description:A microstructured quasicrystalline material is created combining basic unit cells with a lack of perfect periodicity. Quasicrystalline assemblies are a particular case or more general quasiperiodic ones. Recent research carried out by the team in Cardiff on one-dimensional quasicrystalline-based materials has shown that those structures display peculiar properties related to elastic wave propagation. In particular, the dynamic spectra of such waveguides (which reveal the capability of the structure to transmit waves at a given frequency) possess scaling and self-similarity features that can be exploited to design innovative metamaterials able to shield incoming elastic waves and mitigate unwanted vibrations. These features can be described with an elegant mathematical theory that is based on the existence of an invariant function called Kohmoto's invariant. The project will focus on the extension of the above preliminary findings to a fully two- and three-dimensional framework in order to provide guidelines for an effective design of innovative metamaterials based on a quasicrystalline (QC) microstructure. In particular, the following milestones will be pursued: i) identification of the invariants that oversee the dynamical properties of two- and three-D QC materials (1st year); ii) investigation of dispersion diagrams of QC materials and their scaling and self-similarity properties as an extension of what is known in one-dimensional structures (2nd year); iii) study of prototype devices to assess elastic wave attenuation at different frequencies (3rd year); iv) identification of design guidelines for the use of artificial QC-based metamaterials for engineering applications both in seismic and MEMS engineering (final six months).