Force Propagation and Friction in Granular Materials

颗粒材料中的力传播和摩擦

• 批准号: 0137119
• 负责人: Robert Behringer
• 金额: $ 37.5万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-15 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0137119&HistoricalAwards=false
• 关键词: Force; Propagation; Friction; Granular; Materials

This is a combined experiment and theory/modeling condensed matter physics project. The objective is to understand force propagation in granular materials. Granular materials have been the focus of an intensive and growing body of research that also extends to a broader class of materials, such as glasses, colloids, foams and others that exhibit jamming (frozen structures). New techniques are being invented to deal with these materials, which cannot be described in the context of conventional statistical mechanics. Thus, concepts arising from this project have potential to impact a broad range of materials handling problems, which arise with food grains, coal and ores and pharmaceutical powders and other granular materials. In these materials, forces are carried by an inhomogeneous network of so-called stress chains, which form and reform, leading to strong spatio-temporal stress fluctuations. This project will address at least four different systems that exhibit force propagation and fluctuations. Theory/modeling aspects of this work focus on micro/mesoscopic models of stress propagation, while Molecular Dynamics techniques are brought to bear on force fluctuations. This project involves undergraduates, graduate students and post-docs in an integrated program of training and development. More senior students and post-docs train undergrads through appropriate research projects. Graduate students and post-docs receive training in advanced research techniques that prepare them for either academic or industrial careers.This project will focus on the behavior of granular materials, which include a broad spectrum of technologically and industrially relevant products ranging from food grains to coal and ores to pharmaceutical powders. The value added to the US economy in the handling of these materials is estimated to be as much as a trillion dollars a year. However, our understanding of the basic physics of these materials is incomplete, and this translates into a corresponding loss of productivity in dealing with these materials. This project focuses on such basic physics issues as how forces are carried in these materials and how the materials behave when they are subject to applied forces, such as those that might be encountered in handling devices. Important insights sought with this project should include better predictability of materials properties, as well as insight into the limits of this predictability. This project involves undergraduates, graduate students and post-docs in an integrated program of training and development. Grad students and post-docs will help undergrads through appropriate research projects. Undergraduates learn key research techniques, and also training in instrumentation development. Graduate students and post-docs receive training in advanced research techniques that will prepare them for either academic or industrial careers.

这是一个合并的实验和理论/建模凝结物理项目。 目的是了解颗粒材料中的力传播。 颗粒材料一直是一项密集和不断增长的研究的重点，它也扩展到更广泛的材料，例如玻璃，胶体，泡沫和其他表现出干扰的材料（冷冻结构）。 正在发明新技术来处理这些材料，这在常规统计力学的背景下无法描述。 因此，该项目产生的概念可能会影响各种材料处理问题，这些材料处理问题是由食品谷物，煤炭和矿石以及药品粉和其他颗粒状材料产生的。 在这些材料中，力是由所谓的应力链的不均匀网络携带的，这些链形成和改革，导致时空应力的强烈波动。 该项目将至少解决表现出力传播和波动的四个不同的系统。 这项工作的理论/建模方面集中于应力传播的微/介质模型，而分子动力学技术则在力波动上承受。 该项目涉及本科生，研究生和毕业后的培训和发展计划。 越来越多的高级学生和毕业后通过适当的研究项目培训本科生。 研究生和毕业后接受高级研究技术的培训，为学术或工业职业做好准备。该项目将重点介绍颗粒材料的行为，其中包括各种技术和工业相关的产品，从食品谷物到煤炭，矿石，矿石再到药品粉末。 据估计，在处理这些材料方面的价值估计每年高达一万亿美元。 但是，我们对这些材料的基本物理学的理解是不完整的，这转化为处理这些材料时相应的生产力丧失。 该项目着重于这些材料中的力以及材料在受到应用力时的行为，例如在处理设备中可能遇到的材料时的行为。 该项目寻求的重要见解应包括更好的材料特性的可预测性，以及对可预测性限制的见解。 该项目涉及本科生，研究生和毕业后的培训和发展计划。 研究生和毕业后将通过适当的研究项目帮助本科。 本科生学习关键的研究技术以及仪器开发方面的培训。 研究生和职业生涯会接受高级研究技术的培训，这些培训将为学术或工业职业做好准备。