Structural Metamaterials with Saint-Venant Edge Effect Reversal for Static Load Pattern Modification and Recognition

用于静态载荷模式修改和识别的具有圣维南边缘效应反转的结构超材料

基本信息

批准号：
1634577
负责人：
Eduard Karpov
金额：
$ 24.32万
依托单位：
University of Illinois at Chicago
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-15 至 2019-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634577&HistoricalAwards=false
关键词：
Structural Metamaterials Saint Venant Edge

项目摘要

This award supports fundamental research leading to a new class of mechanical metamaterials that, unlike the traditional materials, respond stronger to finer spatial fluctuations in loads than to coarser ones. The notion of metamaterials refers to an exciting class of material systems with engineered internal structure. Specially designed interactions among individual elements of the internal structure lead to a reversal of certain basic properties observed in natural materials. These new properties unveil practical opportunities that can be highly beneficial to the society. For example, photonic metamaterials may be used to fabricate ultrathin lenses for medical applications, and acoustic metamaterials can provide highly efficient sound insulation and earthquake hazard mitigation systems. They will also potentially enable in-situ identification of unsafe loading conditions in structures and building foundations. The paradigm changing aspects of this work will help to inspire undergraduate students and underrepresented groups to participate in the research activities through undergraduate research experiences and the submission of manuscripts in the ASEE Journal of Engineering Education. This research will create a sufficient base of knowledge to enable design and fabrication of these novel metamaterials. The concept of deformation decay spectrum will be introduced on the basis of transfer matrix eigenanalysis of a discrete nonlocal elastic medium in the Fourier domain. Based on the decay spectrum and density of states analyses, phase diagrams will be constructed in the design space of interesting candidate structures to show what combinations of structural parameters are suitable for an actual metamaterial. Availability of asymptotic bandgaps in the decay spectrum will indicate that the metamaterial behavior is achievable for a given nonlocal medium. Mathematically, these bandgaps will require complex-valued decay parameters, as a nonlinear function of the Fourier mode index in a fundamental solution to the governing equation of equilibrium of the nonlocal medium. A complex decay parameter will point out on certain anomalies in the behavior of static Fourier modes in the material, including phase shift and inversion, and mode blockage at surfaces accompanied by the Saint-Venant edge effect reversal. These basic phenomena will be shown to create opportunities for static deformation cloaking, filtering and inversion. More broadly, they will lead to functional metamaterials for qualitative modification and recognition of surface load patterns.

该奖项支持导致新型机械超材料的基础研究，与传统材料不同，这种材料对更精细的负载空间波动的响应比对更粗糙的负载的响应更强。超材料的概念是指一类令人兴奋的具有工程内部结构的材料系统。内部结构的各个元素之间经过特殊设计的相互作用会导致天然材料中观察到的某些基本特性发生逆转。这些新房产带来了对社会非常有益的实际机会。例如，光子超材料可用于制造医疗应用的超薄透镜，声学超材料可提供高效的隔音和地震灾害缓解系统。它们还有可能实现对结构和建筑地基中不安全载荷条件的现场识别。这项工作改变范式的方面将有助于激励本科生和代表性不足的群体通过本科生研究经验和在《ASEE 工程教育杂志》上提交手稿来参与研究活动。这项研究将为这些新型超材料的设计和制造奠定足够的知识基础。基于傅里叶域中离散非局部弹性介质的传递矩阵特征分析，引入变形衰减谱的概念。基于衰变谱和态密度分析，将在有趣的候选结构的设计空间中构建相图，以显示哪些结构参数组合适合实际的超材料。衰变谱中渐近带隙的可用性将表明超材料行为对于给定的非局域介质是可以实现的。从数学上讲，这些带隙将需要复值衰减参数，作为非局部介质平衡控制方程基本解中傅里叶模式指数的非线性函数。复杂的衰减参数将指出材料中静态傅里叶模式行为的某些异常，包括相移和反转，以及伴随圣维南边缘效应反转的表面模式阻塞。这些基本现象将被证明为静态变形隐身、过滤和反演创造机会。更广泛地说，它们将导致用于定性修饰和表面负载模式识别的功能性超材料。