CAREER: Theory and Simulation of the Structure and Mechanical Properties of Non-crystalline Solids

这是一项结合了研究和教育活动的职业补助金。重点是非结晶固体相关性质的理论和模拟。非结晶固体存在于金属、陶瓷、半导体和聚合物中，在工业上有广泛的应用。然而，与对晶体中这些机制的理解相比，对控制非晶体机械特性的原子水平机制的理解很少。这项资助的研究将解决有关非晶体的原子级微观结构的基本问题，因为它们与可测量的机械性能有关。这将通过实施大规模并行计算机模拟方法来模拟非网络形成玻璃对施加应力的原子水平响应来完成。来自这些模拟的数据将使用各种相关函数进行分析，其中一些函数的灵感来自最近对过冷液体和实验波动显微镜研究的研究。一旦分析，来自模拟的数据将为基于表征良好的原子水平过程的非晶塑性变形理论提供基础。这一理论将在数值上实现，连续体模拟将直接与原子结果进行比较，以检验理论的预测。这项研究将大大增加对非晶体材料变形和破坏的理解。此外，本研究将验证这些材料的微观表征诊断。这个研究项目是及时的，因为最近在四个研究领域的重大进展都与这样的调查有关。(1)聚焦于非网状成形玻璃将使本研究能够直接解决对新兴材料大块金属玻璃开发至关重要的问题。(2)这些研究将建立在使用分子动力学模拟技术的最新进展的基础上，以了解玻璃在玻璃转变温度以下的塑性变形。(3)通过关注非网状形成玻璃，本研究将能够直接将当前关于玻璃化转变性质的研究与这种转变的细节对玻璃化固体结构和性质的影响联系起来。(4)获得的关于非网状形成玻璃中程有序和非晶变形之间关系的信息也将有助于扩展波动显微镜技术在预测这些玻璃力学性能方面的适用性。这个计算和理论研究项目将与密歇根大学的一个教育项目相结合，该项目旨在将计算和数学方法完全整合到材料科学与工程核心课程中。这些技术在本科阶段的介绍将分阶段完成，从彻底重新设计本科“动力学和运输”课程开始，并继续进行其他核心课程。PI教授并正在继续开发研究生水平的课程，涵盖分子模拟的计算材料科学方法。本课程也将作为一个教育论坛，讨论在研究项目中开发和使用的教学模拟方法。除了通过大学课程解决教育问题外，该职业计划还包括针对当地社区大学生的有针对性的推广工作。这项工作将解决在华盛顿社区学院的入门科学课程中代表性不足的少数民族学生的动力问题。这项工作的目标是提高这些学生转学到密歇根大学从事工程职业的比率，并为这些学生转学后的成功奠定基础。这是一项结合了研究和教育活动的职业补助金。重点是非结晶固体相关性质的理论和模拟。非结晶固体存在于金属、陶瓷、半导体和聚合物中，在工业上有广泛的应用。然而，与对晶体中这些机制的理解相比，对控制非晶体机械特性的原子水平机制的理解很少。这项资助的研究将解决有关非晶体的原子级微观结构的基本问题，因为它们与可测量的机械性能有关。这将通过实施大规模并行计算机模拟方法来模拟非网络形成玻璃对施加应力的原子水平响应来完成。来自这些模拟的数据将使用各种相关函数进行分析，其中一些函数的灵感来自最近对过冷液体和实验波动显微镜研究的研究。一旦分析，来自模拟的数据将为基于表征良好的原子水平过程的非晶塑性变形理论提供基础。这一理论将在数值上实现，连续体模拟将直接与原子结果进行比较，以检验理论的预测。这项研究将大大增加对非晶体材料变形和破坏的理解。此外，本研究将验证这些材料的微观表征诊断。这个计算和理论研究项目将与密歇根大学的一个教育项目相结合，该项目旨在将计算和数学方法完全整合到材料科学与工程核心课程中。这些技术在本科阶段的介绍将分阶段完成，从彻底重新设计本科“动力学和运输”课程开始，并继续进行其他核心课程。PI教授并正在继续开发研究生水平的课程，涵盖分子模拟的计算材料科学方法。本课程也将作为一个教育论坛，讨论在研究项目中开发和使用的教学模拟方法。除了通过大学课程解决教育问题外，该职业计划还包括针对当地社区大学生的有针对性的推广工作。这项工作将解决在华盛顿社区学院的入门科学课程中代表性不足的少数民族学生的动力问题。这项工作的目标是提高这些学生转学到密歇根大学从事工程职业的比率，并为这些学生转学后的成功奠定基础。

This is a CAREER grant that combines research and education activities. The focus is on the theory and simulation of properties associated with non-crystalline solids. Non-crystalline solids exist as metals, ceramics, semiconductors and polymers, and find wide application in industry. Yet the atomic-level mechanisms that control the mechanical properties of non-crystals are poorly understood compared to the understanding of these mechanisms in crystals. The research on this grant will address fundamental questions regarding the atomic level microstructure of non-crystals as they relate to measurable mechanical properties. This will be accomplished by implementing large-scale parallel computer simulation methods to simulate the atomic level response of non-network forming glasses to applied stresses. The data from these simulations will be analyzed using a variety of correlation functions - some inspired by recent investigations in supercooled liquids and experimental fluctuation microscopy studies. Once analyzed, the data from the simulations will provide the foundation for a theory of non-crystalline plastic deformation based on well characterized atomic level processes. This theory will then be implemented numerically and continuum simulations will be directly compared to atomistic results to test the predictions of the theory. A greatly increased understanding of deformation and failure in non-crystalline materials will result from this investigation. In addition, this research will validate diagnostics for the microscopic characterization of these materials.This research project is timely because significant recent advances in four areas of research each have bearing on such an investigation. (1) Focusing on non-network forming glasses will allow this research to directly address issues critical to the development of an emerging new material, bulk metallic glass. (2) These investigations will build on recent advances using molecular dynamics simulation techniques to develop an understanding of plastic deformation in glasses below the glass transition temperature. (3) By focusing on non-network forming glasses this research will be able to directly link current research regarding the nature of the glass transition to the consequences of the details of this transition for the structure and properties of the glassy solid state. (4) The information gained about the relationship between medium-range order and non-crystalline deformation in non-network forming glasses will also help extend the applicability of fluctuation microscopy techniques to the characterization of these galsses in ways relevant to predicting their mechanical properties.This computational and theoretical research program will be integrated with an educational prgram at the University of Michigan that addresses the need to fully integrate computational and mathematical methods into the Materials Science and Engineering core curriculum. Introduction of these techniques on the undergraduate level will be accomplished in stages starting with a thorough redesign of the undergraduate "Kinetics and Transport" class and continuing with other core classes. The PI has taught, and is continuing to develop, a course on the graduate level covering computational materials science methods for molecular simulation. This course will also serve as an educational forum fo rteaching simulation methods developed and utilized in the research program.In addition to addressing educational issues through the university curriculum, this CAREER program also includes a targeted outreach effort to local community college students. This effort will address the motovational issues of under-represented minority students in introductory science classes at Washtenaw Community College. The goal of this effort is both to increase the rate at which these students transfer to the University of Michigan to pursue engineering as a career and to lay the groundwork for increased success amongst these students post-transfer.%%% This is a CAREER grant that combines research and education activities. The focus is on the theory and simulation of properties associated with non-crystalline solids. Non-crystalline solids exist as metals, ceramics, semiconductors and polymers, and find wide application in industry. Yet the atomic-level mechanisms that control the mechanical properties of non-crystals are poorly understood compared to the understanding of these mechanisms in crystals. The research on this grant will address fundamental questions regarding the atomic level microstructure of non-crystals as they relate to measurable mechanical properties. This will be accomplished by implementing large-scale parallel computer simulation methods to simulate the atomic level response of non-network forming glasses to applied stresses. The data from these simulations will be analyzed using a variety of correlation functions - some inspired by recent investigations in supercooled liquids and experimental fluctuation microscopy studies. Once analyzed, the data from the simulations will provide the foundation for a theory of non-crystalline plastic deformation based on well characterized atomic level processes. This theory will then be implemented numerically and continuum simulations will be directly compared to atomistic results to test the predictions of the theory. A greatly increased understanding of deformation and failure in non-crystalline materials will result from this investigation. In addition, this research will validate diagnostics for the microscopic characterization of these materials.This computational and theoretical research program will be integrated with an educational prgram at the University of Michigan that addresses the need to fully integrate computational and mathematical methods into the Materials Science and Engineering core curriculum. Introduction of these techniques on the undergraduate level will be accomplished in stages starting with a thorough redesign of the undergraduate "Kinetics and Transport" class and continuing with other core classes. The PI has taught, and is continuing to develop, a course on the graduate level covering computational materials science methods for molecular simulation. This course will also serve as an educational forum fo rteaching simulation methods developed and utilized in the research program.In addition to addressing educational issues through the university curriculum, this CAREER program also includes a targeted outreach effort to local community college students. This effort will address the motovational issues of under-represented minority students in introductory science classes at Washtenaw Community College. The goal of this effort is both to increase the rate at which these students transfer to the University of Michigan to pursue engineering as a career and to lay the groundwork for increased success amongst these students post-transfer.