CAREER: Quantifying Local Rearrangements and Their Effects in 3D Granular Materials

职业：量化 3D 颗粒材料中的局部重排及其影响

基本信息

批准号：
1942096
负责人：
Ryan Hurley
金额：
$ 53.54万
依托单位：
Johns Hopkins University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-01 至 2025-04-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1942096&HistoricalAwards=false
关键词：
CAREER Quantifying Local Rearrangements Their

项目摘要

The goal of this CAREER project is to understand how local particle rearrangements give rise to the macroscopic properties of granular materials. Granular materials are found throughout nature and industry as sand, soil, powders, and pills. The mechanical and dynamical properties of these materials are central to engineering design, geological events, and industrial processes. Theories and numerical models have provided links between microscopic processes like particle rearrangements and mechanical and dynamical behavior in these materials. However, much of this prior work has been performed for two-dimensional systems, and the details of the hypothesized links have not been experimentally tested. This project will employ novel X-ray measurements to quantify particle-scale motion and stresses in three-dimensional granular materials. These measurements will be employed to test and improve the existing particle-scale hypotheses that underly theories linking local particle rearrangements to macroscopic behavior. Along with these measurements and tests, new tools will be developed to predict the location, details, and effects of particle-scale rearrangement events. The data and knowledge generated by this research will be integrated into a new graduate-level course on the mechanics of granular materials. The project will involve high-school or undergraduate researchers and engage local artists to develop and disseminate captivating interpretations of the research and research process.This project will use in-situ X-ray tomography and 3D X-ray diffraction measurements of shear-loaded and point-force-loaded 3D granular materials to understand the causes, details, and effects of local particle rearrangements. These measurements will be used to quantitatively test hypotheses underlying theories linking particle rearrangements to macroscopic behavior (e.g., shear transformation zone (STZ) and non-local fluidity (NLF) theories). In particular, the X-ray measurements will allow quantitative assessment of the kinematics of local rearrangements, the associated particle-level strains and stresses, and the length scale of influence of rearrangements within 3D frictional granular materials. In addition, the project will develop new metrics for predicting the locations and effects of particle-scale processes that affect macroscopic behavior that leverage the ability to resolve particle rotations and inter-particle slip. The outcome of the project will be a fundamental understanding of how particle-scale processes give rise to continuum-scale mechanical and dynamical behavior in 3D, frictional behavior, and novel data for validating and extending existing theories.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.

该职业项目的目标是了解局部粒子重排如何产生颗粒材料的宏观特性。颗粒材料在自然界和工业中随处可见，如沙子、土壤、粉末和药丸。这些材料的机械和动力学特性对于工程设计、地质事件和工业过程至关重要。理论和数值模型提供了粒子重排等微观过程与这些材料的机械和动力学行为之间的联系。然而，先前的大部分工作都是针对二维系统进行的，并且假设的链接的细节尚未经过实验测试。该项目将采用新颖的 X 射线测量来量化三维颗粒材料中的颗粒尺度运动和应力。这些测量将用于测试和改进现有的粒子尺度假设，这些假设是将局部粒子重排与宏观行为联系起来的理论基础。除了这些测量和测试之外，还将开发新工具来预测粒子尺度重排事件的位置、细节和影响。这项研究产生的数据和知识将被整合到新的颗粒材料力学研究生课程中。该项目将涉及高中或本科生研究人员，并聘请当地艺术家来开发和传播对研究和研究过程的迷人解释。该项目将使用原位 X 射线断层扫描和 3D X 射线衍射测量剪切载荷和点力加载 3D 颗粒材料，以了解局部颗粒重排的原因、细节和影响。这些测量将用于定量测试将粒子重排与宏观行为联系起来的理论基础假设（例如，剪切转变区（STZ）和非局部流动性（NLF）理论）。特别是，X 射线测量将允许定量评估局部重排的运动学、相关的颗粒级应变和应力，以及 3D 摩擦颗粒材料内重排影响的长度尺度。此外，该项目将开发新的指标来预测影响宏观行为的颗粒尺度过程的位置和影响，利用解决颗粒旋转和颗粒间滑移的能力。该项目的成果将是对粒子尺度过程如何产生 3D 连续尺度机械和动力学行为、摩擦行为以及用于验证和扩展现有理论的新颖数据的基本理解。该奖项反映了 NSF 的法定使命，并具有通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。