Collaborative Research: Dynamics of Surface Instability Propagation in Soft Materials

合作研究：软材料表面不稳定性传播动力学

• 批准号: 1538137
• 负责人: Shengqiang Cai
• 金额: $ 16.25万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1538137&HistoricalAwards=false
• 关键词: Collaborative; Research; Dynamics; Surface; Instability

When soft materials are compressed, their surface often spontaneously forms wrinkles, creases, ridges, or folds with periodic patterns. These patterns are called 'surface instabilities'. Over the past several years, there has been significant interest in understanding how surface instabilities form, as they are ubiquitous in biological systems and have found wide use in engineering applications ranging from microfabrication to soft robotics. However, nearly all of the past studies have focused on understanding how surface instabilities form under very slow compression, or have neglected the dynamics leading to this event. This award will investigate how surface instabilities form and propagate across the surface of the material as a result of fast compression or impacts. The speed of the event causing the instability is critical as it yields fundamentally unique phenomena, which are prevalent in most physical systems, but still not well understood. The improved understanding gained as part of this fundamental research will impact a broad range of applications. For example, because of the role of surface instabilities in friction, this research will positively affect engineering applications with moving soft materials in contact. It will also lead to improved understanding of the dynamics of sandwich beam composites, and to improved impact absorbers, shock protective systems, and novel soft electronics devices. In addition to the research goals, this project has a significant education and outreach component that will positively affect students from K-12 through graduate levels, and will increase the involvement of underrepresented students in STEM fields.The research objective of this multidisciplinary, collaborative project is to investigate the initiation and propagation of surface instabilities in soft materials under dynamic loading, using a combined theoretical, computational, and experimental approach. Experimental characterization will be conducted using a combination of drop tower, high-speed video, and laser ultrasonic test methods. Dynamic surface instability propagation will be modeled analytically, and computationally using nonlinear finite element techniques. This project will provide significant intellectual contribution by answering open questions including: What are the conditions for initiating the propagation of surface instabilities, and how do they propagate? How does the propagation of surface instabilities lead to material failure? And how can the propagation of surface instabilities be manipulated? More generally, as there have been almost no investigations into the dynamics of propagating surface instabilities, this investigation will open a new class of instability-based surface waves and provide an improved understanding of dynamic phenomena in soft materials.

当压缩软材料时，它们的表面通常会自发形成带有周期性图案的皱纹，折痕，山脊或折叠。这些模式称为“表面不稳定性”。在过去的几年中，人们对了解表面不稳定性在生物系统中无处不在，并且在工程应用中广泛使用，从微结合到软机器人技术一直存在着浓厚的兴趣。但是，几乎所有过去的研究都集中在理解在非常缓慢的压缩下形成表面不稳定性，或者忽略了导致该事件的动态。该奖项将研究表面不稳定性如何形成并在整个材料表面繁殖，这是由于快速压缩或影响的结果。导致不稳定性的事件的速度至关重要，因为它产生了从根本上独特的现象，在大多数物理系统中都是普遍的，但仍然不太了解。作为这项基础研究的一部分，获得的改善理解将影响广泛的应用。例如，由于表面不稳定性在摩擦中的作用，这项研究将积极影响工程应用，并通过移动的软材料接触。这也将提高人们对三明治束复合材料的动力学的了解，并改善吸收剂，冲击保护系统和新型软电子设备。除了研究目标外，该项目还具有重要的教育和外展成分，将对来自K-12到研究生水平的学生产生积极影响，并将增加代表性不足的学生参与STEM领域的研究。该多学科，协作项目的研究目标是研究在软载荷下使用动态载荷的材料中的表面启动和繁殖的方法，并使用动态载荷进行了综合方法，并进行了组合的方法，并进行了综合实验，并进行了综合的实验。实验表征将使用滴塔，高速视频和激光超声测试方法的组合进行。动态表面不稳定性传播将通过非线性有限元技术进行分析和计算进行建模。该项目将通过回答开放问题，包括：启动表面不稳定性的传播的条件以及它们如何传播的条件？表面不稳定性的传播如何导致物质故障？如何操纵表面不稳定性的传播？更普遍的是，由于几乎没有对传播表面不稳定性的动力学进行的研究，因此该研究将打开一类新的基于不稳定性的表面波，并提高人们对软材料中动态现象的了解。