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

由于具有前所未有的成分和结构复杂性的工程系统的增材制造的发展，在具有由其工程结构决定的令人兴奋的机械性能的建筑材料方面取得了重大进展。在动力学领域，使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，并将其应用于较大幅度负载中的机械信号控制（例如，在冲击事件期间提供保护）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。所有级别的学生将学习材料科学与工程，计算和分析机械建模，先进制造和传感的概念和技术。此外，研究小组将把这些努力与两个机构的本科生研究项目、外展工作和教育材料开发相结合，为所有年龄段的代表性不足的群体提供研究机会。（K-12，本科，这项工作的目的是了解几何和非线性传播之间的基本联系，包括旋转多边形的柔顺机械超材料中的线性波。而不是限制范围的周期性系统在以前的工作中，超材料的几何形状将局部定制，和不均匀性将被利用，以实现目标的动态响应，如最大的能量吸收，孤子透镜，和运动。该多方面的研究计划将结合理论，数值和实验活动，以产生对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，研究分为三个方面，重点是（1）非均匀性对非线性波传播的影响，（2）通过非线性波实现系统动力学的可重构性，以及（3）通过机器学习优化几何形状和缺陷，以实现目标动态特性（能量吸收，转向波，运动等）。该项目由土木、机械和工业创新部的动力学、控制和系统诊断（DCSD）以及材料和结构力学（MOMS）项目共同资助。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。

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.