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

EPSRC研究范围：连续介质力学(生长)，结构力学(维护)描述：一种微结构准晶材料是将基本单胞与缺乏完美周期性相结合而产生的。准晶组件是一种特殊情况或更一般的准周期组件。卡迪夫的研究小组最近对一维准晶材料进行的研究表明，这些结构显示出与弹性波传播有关的特殊性质。特别是，这种波导的动态频谱(揭示了结构在给定频率下传输波的能力)具有标度和自相似特征，可以利用这些特征来设计能够屏蔽输入的弹性波并缓解不必要的振动的创新超材料。这些特征可以用一种优雅的数学理论来描述，该理论基于一种称为Kohmoto不变量的不变量函数的存在。该项目将侧重于将上述初步发现扩展到完全的二维和三维框架，以便为基于准晶(QC)微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)确定监督二维和三维QC材料动力学性质的不变量(第一年)；ii)研究QC材料的色散图及其比例和自相似特性，作为一维结构中已知的扩展(第二年)；iii)研究评估不同频率下的弹性波衰减的原型装置(第三年)；iv)确定在地震和MEMS工程中使用人工QC超材料的设计指南(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).