Stress Testing Theories of the Glass and Jamming Transitions Using Hyperellipsoids

使用超椭球体的玻璃和干扰转变的应力测试理论

• 批准号: 2026271
• 负责人: David Simmons
• 金额: $ 31.5万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2026271&HistoricalAwards=false
• 关键词: Stress; Testing; Theories; Glass; Jamming

NONTECHNICAL SUMMARYThis award supports theoretical and computational research and education in the fields of solidification processes, statistical mechanics, and computer simulations. How does a given liquid decide whether to crystallize or to form a disordered solid like window glass when it is cooled? This question remains unanswered, and is a principal focus of current materials research. Glass-formation is closely related to the jamming transition, the solidification of a granular material, like sand or coffee beans, that occurs when it is compressed. Although great advances in theories of the glass-jamming transition have been made over the past decade, most of these theories assume particles are spherical. This is a potentially serious limitation because very few real-world glassy and granular materials are composed of spherical molecules or grains.This project aims to advance our knowledge of the glass-jamming transition by conducting a coherent research program that focuses upon its dependence on particle asphericity. The research will systematically relate differences in the structure of glassy and jammed systems composed of model ellipsoidal particles to differences in particle shape and sample preparation protocol. The relatively low computational cost of the ellipsoidal-particle model will be exploited to explore relevant parameter spaces far more broadly than is feasible for chemically-detailed models. Key questions to be addressed are: (1) Does the importance of particle anisotropy decrease as spatial dimension increases? and (2) To what extent do the peculiar features of ellipsoids’ jamming transitions influence their glass transitions? The planned studies are designed with the aim to contribute maximally to the long-term goal of obtaining a level of physical understanding sufficient to develop predictive design principles for granular and glassy materials with tailorable structural, mechanical, and acoustic properties. This award will fund the training of one PhD student and one undergraduate student in granular and glass physics, statistical mechanics, and computer simulations. The PI will also develop and disseminate “EllJam”, an iPhone/iPad app that illustrates the solidification physics of 2D ellipsoids. Playing with parameters such as the particle aspect ratio and compression rate will allow the user to discover and distinguish parameter values leading to crystalline solids from those which lead to disordered solids, and hence to develop some basic intuition for which factors control the outcome of solidification. This app is intended to capture the interest of K-12 students and young researchers. TECHNICAL SUMMARYThis award supports theoretical and computational research and education in the fields of solidification processes, specifically, the glass-jamming transition, statistical mechanics, and computer simulations. While the importance of particle anisotropy in controlling macroscopic properties of glassy and jammed systems has long been recognized, it is only within the past decade that the development of cheap high-output 3D printers has allowed production of grains with a wide variety of precisely specified shapes. Advances in synthesis techniques have allowed comparable shape control for colloids as well as preparation of orientationally-ordered small-molecule glasses. Over this time, computers have become powerful enough to simulate large systems of aspherical particles over long timescales. Although great advances in theories of the glass-jamming transition have been made over the past decade, most of these theories assume particles are spherical and hence cannot capture the effects of particle anisotropy. This is a potentially serious limitation because very few real-world glassy and granular materials are composed of spherically symmetric molecules or grains.The PI will carry out studies that will systematically relate differences in the structure of glassy and jammed systems composed of ellipsoidal particles to differences in particle shape via a coherent program of coarse-grained simulations and analytic modeling. The PI will also “stress-test” recently developed high-dimensional theories of the glass-jamming transition by determining whether they remain at least qualitatively accurate for systems composed of aspherical particles. Specifically, the research team will first develop a parallel molecular dynamics code for simulating hyperellipsoids. Then it will conduct simulations and analytic work aimed at determining how coupled dimension and particle-aspect-ratio-dependent effects influence both jamming and the thermal glass transition. Key amongst the questions to be answered by these studies are: (1) Does particle anisotropy become less important as spatial dimension increases and the tendency of particles to locally order decreases — and if it does, how rapidly? and (2) To what extent do the peculiar features of jamming transitions in ellipsoids, more precisely jamming densities that become singular as the aspect ratio of a particle approaches unity, influence their thermal glass transitions? Answering these questions will contribute to the soft matter theory community’s long-term goal of obtaining a level of physical understanding sufficient to develop predictive design principles for granular and glassy materials with tailorable structural, mechanical, and acoustic properties. This award will fund the training of one PhD student and one undergraduate student in granular and glass physics, statistical mechanics, and computer simulations. The PI will also develop and publicize “EllJam”, an iPhone/iPad app that illustrates’ 2D ellipsoids’ jamming physics. The user will be able to choose the system size, the particle aspect ratio, and the compression rate, and then watch how ellipsoid jamming varies with these parameters. The user will also be able to choose between monodisperse systems which tend to crystallize in 2D and the 50:50 bidisperse systems typically employed in jamming studies. This app should be of interest to both K-12 students and young researchers.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.

非技术摘要这一奖项支持固化过程，统计力学和计算机模拟领域的理论和计算研究和教育。给定的流动性如何在冷却时是否结晶或形成像窗玻璃这样的无序实心？这个问题仍未得到答复，并且是当前材料研究的主要重点。玻璃形成与干扰过渡密切相关，即在压缩时发生的颗粒材料（如沙子或咖啡豆）的凝固。尽管在过去十年中已经取得了巨大的进步，但这些理论中的大多数都认为粒子是球形的。这是一个潜在的严重限制，因为很少有现实世界中的玻璃状和颗粒状材料由球形分子或谷物组成。该项目旨在通过进行一项连贯的研究计划来促进我们对玻璃杀伤过渡的了解，该研究集中于其对粒子无与无精神的依赖。这项研究将系统地将由模型椭圆形颗粒组成的玻璃状和堵塞系统的结构差异与粒子形状和样品制备方案的差异联系起来。将探索椭圆形粒子模型的相对低计算成本，以探索相关参数空间远比化学详细模型的可行性要广泛得多。要解决的关键问题是：（1）随着空间维度的增加，粒子各向异性的重要性是否会降低？ （2）椭圆形的干扰过渡的特征在多大程度上影响其玻璃过渡？计划的研究旨在最大程度地提高长期目标，即获得足以开发具有可定制结构，机械和声学特性的颗粒状和玻璃材料的预测设计原理。该奖项将资助一名博士生和一名粒状和玻璃物理学，统计力学和计算机模拟的本科生的培训。 PI还将开发和传播“ EllJam”，这是一种iPhone/iPad应用程序，说明了2D椭圆形的固化物理。使用诸如颗粒纵横比和压缩率之类的参数播放将使用户发现和区分参数值，从而导致结晶固体与导致固体无序的固体的参数值，从而开发一些基本直觉，以控制哪些因素控制固体的结果。该应用程序旨在吸引K-12学生和年轻研究人员的兴趣。技术摘要这一奖项支持固化过程领域的理论和计算研究和教育，特别是玻璃界面过渡，统计力学和计算机模拟。虽然粒子各向异性在控制玻璃和障碍系统的宏观特性中的重要性长期以来已经认识到，但仅在过去的十年内，便宜的高输出3D打印机的发展才允许生产具有多种精确指定形状的晶粒。合成技术的进步允许对结石的形状控制以及定向有序的小分子玻璃的制备。在这段时间里，尽管在过去的十年中，这些计算机已经实现了强大，尽管在玻璃界过渡的理论方面取得了巨大进步，但这些理论中的大多数都假设粒子是球形的，因此无法捕获粒子各向异性的影响。这是一个潜在的严重限制，因为很少有现实世界的玻璃状和颗粒状材料由球形对称分子或谷物组成。PI将进行研究，这些研究将系统地将玻璃状和危机系统结构的差异与椭圆形颗粒组成的结构相关联，以通过粒子形状在粒子形状上，以通过粗略的模拟和分析模型来差异。 PI还将“应力测试”最近通过确定由非球形颗粒组成的系统至少保持相当准确的玻璃杀伤过渡的高维理论。具体而言，研究团队将首先开发一个平行的分子动力学代码，用于模拟高层。然后，它将进行模拟和分析工作，以确定耦合维度和粒子依赖性依赖性效应如何影响干扰和热玻璃转变。这些研究要回答的问题的关键是：（1）随着空间维度的增加以及粒子局部秩序下降的趋势，粒子各向异性是否变得不那么重要？ （2）在椭圆形中干扰过渡的特殊特征在多大程度上，更精确地堵塞了密度，这些密度随着粒子的纵横比接近统一的纵横比而变得奇异，影响了他们的热玻璃跃迁？回答这些问题将有助于软材料理论社区的长期目标，即获得足以开发具有可定制结构，机械和声学特性的颗粒和玻璃材料的预测设计原理的物理理解水平。该奖项将资助一名博士生和一名大学生玻璃物理学，统计机械和计算机模拟的培训。 PI还将开发和宣传“ EllJam”，这是一个iPhone/iPad应用程序，说明了2D椭圆形的堵塞物理。用户将能够选择系统尺寸，颗粒纵横比和压缩率，然后观察椭圆形的挤压用户也将能够在倾向于在2D和50:50 BIDISPERSE的单分散系统之间进行选择，而50:50 Bidisperse系统通常在干扰研究中使用。该应用程序应该引起K-12学生和年轻研究人员的兴趣。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响评估标准来评估，被认为是珍贵的支持。

项目成果

Structure of jammed ellipse packings with a wide range of aspect ratios

各种长径比卡紧椭圆填料的结构

• DOI: 10.1039/d3sm00705g
• 发表时间: 2023
• 期刊: Soft Matter
• 影响因子: 3.4
• 作者: Rocks, Sebastian;Hoy, Robert S.
• 通讯作者: Hoy, Robert S.

Ultraslow Settling Kinetics of Frictional Cohesive Powders

摩擦粘性粉末的超慢沉降动力学

• DOI: 10.1103/physrevlett.130.166102
• 发表时间: 2023
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Nan, Kai;Hoy, Robert S.
• 通讯作者: Hoy, Robert S.

Craze Extension Ratio of Semiflexible Polymer Glasses

半柔性聚合物玻璃的裂纹延伸率

• DOI: 10.1021/acs.macromol.3c01608
• 发表时间: 2023
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Nan, Kai;Hoy, Robert S.
• 通讯作者: Hoy, Robert S.

Efficient d -dimensional molecular dynamics simulations for studies of the glass-jamming transition

用于研究玻璃干扰转变的高效 d 维分子动力学模拟

• DOI: 10.1103/physreve.105.055305
• 发表时间: 2022
• 期刊: Physical Review E
• 影响因子: 2.4
• 作者: Hoy, Robert S.;Interiano-Alberto, Kevin A.
• 通讯作者: Interiano-Alberto, Kevin A.

Thermodynamic stability of hard sphere crystals in dimensions 3 through 10

3 至 10 维硬球晶体的热力学稳定性

• DOI: 10.1140/epje/s10189-021-00104-y
• 发表时间: 2021
• 期刊: The European Physical Journal E
• 作者: Charbonneau, Patrick;Gish, Caitlin M.;Hoy, Robert S.;Morse, Peter K.
• 通讯作者: Morse, Peter K.