CAREER: Exploiting Time Dependent Behavior and Structure in Developing Programmable Materials

这项教师早期职业发展（Career）资助支持新一代可编程材料的开发，这些材料可以实时控制和监测振动和冲击事件。这项技术有可能影响各种应用，从改善传感和监测基础设施到彻底改变新兴的智能包装领域。例如，由于老化和/或温度变化，系统的条件会随着时间的推移而变化，这些材料允许对系统的能量吸收能力进行原位修改，因此，它们可以降低更换减振设备的成本。这项CAREER资助将引入新的机制来编程这些材料的刚度和随时间变化的机械和惯性行为。教育外展将通过提供基于项目的体验活动来吸引学生，培养他们对数学在现实世界中的应用的理解，解决边缘化学生所面临的系统性障碍，这些学生往往被安排在不太严格的数学课程中。这些努力还旨在向PI的研究团队展示STEM推广的重要性，其目标是增加学术界的多样性和包容性。本CAREER项目的研究目标是研究非均质机械超材料中拓扑与非线性和随时间变化的材料行为之间相互作用的物理学，并建立数学基础。应用范围从振动抑制和减震到具有自传感能力的超材料的发展。本研究将填补机械超材料概念化的系统技术和理论的基础知识空白。该项目工作将重点关注具有非均质性的超材料，其来源包括：1)弹性体矩阵拓扑中的包含物，称为“数字元素”；2)行为主要为粘弹性的材料与行为主要为弹性和/或超弹性的材料的组合。这些数字元件的选择性放置/和/或移除允许对单个主机结构进行系统编程，以举例说明作为振动系统组件时导致一系列动态响应的惯性和弹性行为。我们假设复合粘弹性和超弹性材料将允许宿主结构具有定制的新型应变相关响应。这些活动将发展基本的理解和建立数学框架，利用动力系统理论以及分析和数值建模，材料表征和实验测试来利用这些现象。由此产生的框架将用于改进具有自我感知能力的超材料的开发。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。

This Faculty Early Career Development (CAREER) grant supports the development of a new generation of programmable materials that can control and monitor vibrations and shock events in real time. This technology has the potential to influence various applications ranging from improving the sensing and monitoring infrastructure to revolutionizing the emerging field of smart packaging. As an example, these materials allow for in-situ modification of the energy absorbing capabilities of systems whose conditions can change over time due to aging and/or due to changing temperatures, and, as such, they can reduce the cost of replacing vibration reduction equipment. This CAREER grant will introduce new mechanisms to program the stiffness and time-dependent mechanical and inertial behavior of these materials. The educational outreach will address systemic barriers placed upon marginalized students, who are often placed in less rigorous mathematics courses, by offering project-based experiential activities to engage students and foster an understanding of the applications of mathematics in a real-world context. These efforts also aim to demonstrates to the PI's research team the importance of STEM outreach with the goal of increasing diversity and inclusion in academia.The research goal of this CAREER project is to investigate the physics, and establish a mathematical foundation, that governs the interplay between topology and nonlinear and time-dependent material behavior in heterogeneous mechanical metamaterials. Applications range from vibration suppression and shock absorption to the development of metamaterials with self-sensing capabilities. This research will fill a fundamental knowledge gap in systematic techniques and theories that conceptualize mechanical metamaterials. The project work will focus on metamaterials with heterogeneity that arises from: 1) an inclusion in the topology of an elastomeric matrix, coined a ``digital element", and 2) the combination of materials whose behavior is primarily viscoelastic with a material whose behavior is primarily elastic and/or hyperelastic. The selective placement /and or removal of these digital elements allows for the systematic programming of a single host structure to exemplify a host of inertial and elastic behaviors leading to a range of dynamic responses when used as a component in a vibratory system. We hypothesize that the composite viscoelastic and hyperelastic materials will allow the host structure to have tailored novel strain dependent responses. The activities will develop the fundamental understanding and establish the mathematical framework needed to exploit these phenomena using the theory of dynamical systems along with analytical and numerical modeling, material characterization, and experimental testing. The resulting framework will then be used to improve the development of metamaterials with self-sensing capabilities.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.