Collaborative Research: Nanofluidics Enabled Attenuation of Dynamic Impacts and Stress Waves

为了保护人员和重要的基础设施和设备，一直在追求动态冲击和应力波的衰减。然而，大多数现有保护材料和结构的应力波缓解程序是基于材料和结构的不可恢复屈曲和/或塑性变形所支撑的能量吸收。此外，这种变形机制的激活时间远远长于动态冲击和应力波通过这些保护材料传播所需的时间。在纳米流体中，液体在外部压力或应力的作用下被迫进入具有疏水表面的纳米级通道，有望为衰减机械波能量提供一种引人注目的途径。该机制已被常规应用于表征多孔材料的纳米孔尺寸分布，但现在为保护材料和结构的设计提供了一个新的范例，完全不同于传统的能量吸收机制。该项目的总体目标是研究和理解纳米流体能够减轻动态冲击和应力波，特别关注三维纳米孔网络中的纳米流体。这个合作项目还将对教育产生广泛的影响，包括对研究生和本科生的专业培训，以及与当地高中的激励互动。本合作项目旨在系统地研究非润湿液-固纳米多孔复合材料的纳米流体学，并探索其减轻动态冲击和应力波的潜在保护机制。为此，建议的研究将集中在三个方面：(1)利用原子模拟研究和揭示高速加载下非润湿液-固纳米孔结构中的纳米流体学；(2)建立纳米流体能量捕获机制的理论模型，量化纳米流体对动态冲击和应力波的响应；(3)利用非润湿液-固纳米孔材料平台设计并开展高应变速率下的验证实验。纳米流体能量捕获机制将刷新现有的受应力波保护材料和结构的设计策略，从而彻底改变基础纳米流体和应用技术。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。

Attenuation of dynamic impacts and stress waves has been pursued to protect personnel and important infrastructures and devices. However, mitigation procedures of stress waves of most of existing protection materials and structures are based on energy absorption underpinned by unrecoverable buckling and/or plastic deformation of materials and structures. Besides, the activation time of such deformation mechanisms is much longer than the time needed for dynamic impacts and stress waves propagate through these protection materials. Nanofluidics, in which the liquid is forced into nanoscale channels with hydrophobic surface by an external pressure or stress, is expected to provide a compelling route for attenuating mechanical wave energy. This mechanism has been routinely applied to characterize the nanopore size distributions of porous materials, but now offers a new paradigm for the design of protection materials and structures, entirely distinct from conventional energy absorption mechanisms. The overarching goal of this project is to investigate and understand nanofluidics enabled mitigation of dynamic impacts and stress waves with particular focuses on nanofluidics in three-dimensional nanoporous networks. This collaborative project will also provide a broad impact on education including professional trainings to both graduate and undergraduate students, and on outreach including inspiring interactions with local high schools. The objective of this collaborative project is to systematically investigate the science of nanofluidics in non-wetting liquid-solid nanoporous composite materials, and to explore its underlying protection mechanism for mitigating dynamic impacts and stress waves. To this end, the proposed research will focus on three tasks: (i) to investigate and unveil the science of nanofluidics in non-wetting liquid-solid nanoporous structures under a high speed loading using atomistic simulations, (ii) to develop a theoretical model of nanofluidic energy capture mechanism to quantify nanofluidic responses to dynamic impacts and stress waves, and (iii) to design and carry out verification experiments at high strain rates by employing non-wetting liquid-solid nanoporous materials platforms. The nanofluidic energy capture mechanism will refresh existing design strategies of protection materials and structures subjected to stress waves, thereby revolutionizing both fundamental nanofluidics and application technologies.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.