Collaborative Research: Consistent Treatment of Boundaries and Interfaces in Metamaterials

这个项目是研究超材料，以实现所需的行为和功能，这将是很难的，如果不是不可能的，在自然发生的材料中找到。超材料在许多行业和国防领域有着广泛的应用，可以彻底改变诸如降噪、隔振、能量收集、雷达和声纳以及传感器开发等用例。超材料研究的一个基本问题是，这种系统在其边界附近的动态响应目前还知之甚少，特别是与其内部的响应相比。这一缺陷阻碍了超材料技术从研究向工业的过渡。该奖项支持基础研究，为理解超材料研究中的边界和界面问题提供所需的知识。它涉及多个学科，包括声学和弹性超材料，逆向设计和优化，材料科学。多学科的方法将有助于积极影响未来的工程教育。该团队将对过渡层进行理论和计算分析，并使用逆向设计原理来创建控制机械波传播的设备。他们还将进行实验来验证模型并测试所创建设备的性能。这项资助的主要技术目标是提供一种一致的方法来解决声学和弹性超材料有限域上的动态边界值问题。目前的方法要么涉及微观理论（具有非常高的材料参数）或精确的，但非局部的边界条件（制定与Fredholm积分方程）。前者与超材料器件设计的大部分机制（如转换方法）不兼容，后者复杂到足以使其目前几乎无法使用。因此，理想的超材料设计，当在实践中实现时，表现出显着的和知之甚少的性能退化。通过这笔赠款，该团队试图通过以下方式解决这个问题：1）利用并专注于局部超材料，2）将它们与过渡层耦合。据推测，这两个想法将使它易于处理，以解决广泛的边界值问题，涉及任意有限样本，从而克服了该领域的一个关键障碍。机械超材料的技术前景取决于对这种设计的散射的精确建模，这受到界面处理的显著影响。该项目由材料结构力学（MOMS）计划和动力学、控制和系统诊断（DCSD）计划共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project is study metamaterials to achieve desired behaviors and functions that would be hard, if not impossible, to find in naturally occurring materials. Metamaterials have broad applications in numerous industries and defense that can revolutionize use-cases such as noise mitigation, vibration isolation, energy harvesting, radar and sonar, and sensor development. A fundamental issue with metamaterials research is that the dynamic response of such systems near their boundaries is currently poorly understood, especially in contrast to their response in their interior. This deficiency has slowed the transition of the technology of metamaterials from research to industry. This award supports fundamental research to provide needed knowledge for the understanding of the boundary and interface issues in metamaterials research. It involves several disciplines including acoustic and elastic metamaterials, inverse design and optimization, and materials science. The multi-disciplinary approach will help positively impact engineering education of the future. The team will perform theoretical and computational analysis of transition layers and use inverse design principles to create devices that control propagation of mechanical waves. They will also conduct experiments to verify the models and test the performance of the devices created. The broad technical goal of this grant is to provide a consistent method for the solution of dynamic boundary value problems on finite domains of acoustic and elastic metamaterials. Current approaches either involve micromorphic theories (with a very high number of material parameters) or exact but nonlocal boundary conditions (formulated with Fredholm integral equations). The former is incompatible with much of the machinery of metamaterial device design (such as transformation methods) and the latter is complex enough to make its use at the moment nearly untenable. As a consequence, ideal metamaterial designs, when realized in practice, demonstrate significant and poorly understood performance degradations. Through this grant, the team seeks to solve this issue by 1) utilizing and focusing on local metamaterials and 2) coupling them with transition layers. It is hypothesized that these two ideas will make it tractable to solve a wide range of boundary value problems involving arbitrary finite samples, thus overcoming a critical obstacle in the field. The technological promise of mechanical metamaterials is hinged upon accurate modeling of scattering off such designs, which is significantly affected by the handling of interfaces. This grant seeks to overcome this major obstacle towards robust designs of micro-structured media.This project is jointly funded by Mechanics of Materials & Structures (MOMS) Program and Dynamics, Control and Systems Diagnostics (DCSD) Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.