Collaborative Research: Programming Non-Linear Waves in Compliant Mechanical Metamaterials

由于工程系统的增材制造技术的发展，其组成和结构的复杂性达到了前所未有的水平，建筑材料已经取得了重大进展，这些材料具有由其工程结构决定的令人兴奋的机械性能。在动力学领域，利用工程结构产生新特性的想法历来主要集中在线性波上。这项工作旨在了解非线性波在机械超材料中的传播，并将其应用于较大振幅载荷下的机械信号控制（例如，在冲击事件中提供保护）和可重构软结构（例如，软机器人的运动）。这项研究将促进跨学科的研究和教学。所有层次的学生将学习材料科学和工程、计算和分析机械建模、先进制造和传感的概念和技术。此外，研究团队将把这些努力与两所机构的本科生研究项目、推广工作和教育材料开发结合起来，为所有年龄段（K-12、本科生和研究生）的代表性不足的群体提供研究机会。这项工作的目的是了解几何和非线性波在由旋转多边形组成的柔顺机械超材料中的传播之间的基本联系。而不是将范围限制在周期系统在以前的工作中，超材料的几何形状将局部定制，不均匀性将被利用来实现目标动态响应，如最大能量吸收，孤子透镜，和运动。多方面的研究计划将理论，数值和实验活动交织在一起，以产生基于旋转单元的机械超材料的非线性动态行为的新见解。为了实现这一目标，研究分为三个重点，重点关注(1)非均匀性对非线性波传播的影响，(2)非线性波对系统动力学的可重构性，以及(3)通过机器学习对几何和缺陷进行优化，以实现目标动态特性（能量吸收、转向波、运动等）。该项目由动力学、控制和系统诊断（DCSD）以及民用、机械和工业创新部门的材料和结构力学（mom）项目共同资助。该奖项反映了美国国家科学基金会的法定使命，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。

Enabled by developments in the additive manufacturing of engineered systems with unprecedented levels of compositional and structural complexity, there have been major advances in architected materials that possess exciting mechanical properties dictated by their engineered structure. Within the realm of dynamics, the idea of using engineered structures to produce novel properties has been historically focused primarily on linear waves. This work seeks to understand the propagation of non-linear waves in mechanical metamaterials with application toward control of mechanical signals in larger-amplitude loading (for example, to provide protection during impact events) and toward reconfigurable soft structures (for example, locomotion of soft robots). This research will promote interdisciplinary research and teaching. Students of all levels will learn concepts and techniques from materials science and engineering, computational and analytic mechanical modeling, advanced manufacturing, and sensing. Moreover, the research team will integrate these efforts with undergraduate research programs, outreach efforts, and educational material development at both institutions to provide research opportunities to underrepresented groups of all ages (K-12, undergraduate, and graduate).The objective of this work is to understand the fundamental connection between geometry and the propagation of non-linear waves in compliant mechanical metamaterials comprising rotating polygons. Rather than limiting the scope to periodic systems as in previous work, the geometry of the metamaterials will be locally tailored, and inhomogeneities will be harnessed to achieve target dynamic responses such as maximal energy absorption, soliton lensing, and locomotion. The multi-faceted research program will intertwine theoretical, numerical, and experimental activities to generate new insights into the non-linear dynamic behavior of mechanical metamaterials based on rotating units. To achieve this, the research is organized into three thrusts, focusing on (1) the effect of inhomogeneities on the propagation of non-linear waves, (2) reconfigurability of system dynamics via non-linear waves, and (3) optimization of geometry and defects via machine learning to achieve targeted dynamic properties (energy absorption, steering waves, locomotion, etc.).This project is co-funded by the Dynamics, Control, and Systems Diagnostics (DCSD) and the Mechanics of Materials and Structures (MOMS) programs in the Civil, Mechanical, and Industrial Innovation Division.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.