CAREER: Fundamental Studies of Glassy Polymer Mechanics

职业：玻璃态聚合物力学的基础研究

• 批准号: 1555242
• 负责人: Robert Hoy
• 金额: $ 49万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1555242&HistoricalAwards=false
• 关键词: CAREER; Fundamental; Studies; Glassy; Polymer

NONTECHNICAL SUMMARYThis CAREER award supports computational and theoretical research, and education in the field of glassy polymer mechanics. The industrial importance of understanding strength and failure of polymeric materials, such as structural plastics, has made quantitatively predicting their entire range of mechanical response an important goal of physical polymer science. Polymeric materials are composed of long chain molecules with repeating chemical units. Chemically different polymers exhibit dramatically different mechanical properties; large differences in mechanical responses play a major role in determining the stability of these materials against fracture. Understanding these different mechanical responses is critical to developing new high-performance materials as well as predicting the failure behavior and operational lifetime of existing systems, yet progress towards understanding them has been slow. Explaining the variety of behaviors observed has remained an open problem and microscopic, physics-based models are so far unsatisfactory at a predictive level. While computer simulations can provide essentially complete information on phenomena occurring during deformation of model systems, physical interpretation of this information can be difficult in the absence of an overarching theoretical framework. Recently developed candidate frameworks that have not yet been tested by simulation provide an opportunity for transformative advance. The research involves coordinated modeling that will exploit this opportunity and other opportunities that have emerged from recent experimental work. Progress toward the long term goals of this project will facilitate development of strong, lightweight structural plastics that can be used in applications ranging from automobiles to armaments. This project contributes to training two students in polymer physics, statistical mechanics, and computer simulations and contributes to developing a modern materials workforce. This award also contributes to enhance access of underrepresented minority students, including African Americans, Hispanics, and Native Americans, to higher degrees in physics through participation in the American Physical Society Bridge Program. The PI plans to assume primary responsibility for local Bridge student recruitment, admissions, and mentoring, as well as teaching a Science and Technology Engineering and Mathematics Professional Development course. The PI will also continue developing non-cognitive criteria for admissions and work to ensure their implementation within the Bridge Program and the local Applied Physics PhD program.TECHNICAL SUMMARYThis CAREER award supports computational and theoretical research, and education in the field of glassy polymer mechanics. The project includes a program of simulations and analytical modeling that will significantly enhance basic physical understanding of how the mechanical properties of polymer glasses relate to their microscopic interactions and mesoscale order. Simulations will systematically relate differences in mechanical response to differences in micro- and meso-structure by varying local chain stiffness, sample preparation protocol, and deformation history, including temperature. Systems will be deformed to fracture in order to determine how these factors influence ultimate mechanical properties, such as ductility and toughness.The relatively low computational cost of the coarse-grained approach will be exploited to explore relevant parameter spaces far more broadly than is feasible for chemically detailed models. Analytical work will both complement the simulations and extend recently developed microphysics-based theories of polymer mechanics, through an iterative process wherein simulation uncovers problems with theories, the theories are improved as needed, and then used to make new predictions that will be tested by carefully designed follow-up simulations. This combined approach is designed to contribute maximally to the community's long term goal to obtain a level of physical understanding sufficient to develop predictive materials design principles to tailor mechanical response. Progress toward the long term goals of this project will facilitate development of strong, lightweight structural plastics that can be used in applications ranging from automobiles to armaments. This project contributes to training two students in polymer physics, statistical mechanics, and computer simulations and contributes to developing a modern materials workforce. This award also contributes to enhance access of underrepresented minority students, including African Americans, Hispanics, and Native Americans, to higher degrees in physics through participation in the American Physical Society Bridge Program. The PI plans to assume primary responsibility for local Bridge student recruitment, admissions, and mentoring, as well as teaching a Science and Technology Engineering and Mathematics Professional Development course. The PI will also continue developing non-cognitive criteria for admissions and work to ensure their implementation within the Bridge Program and the local Applied Physics PhD program.

非技术总结这个职业奖支持计算和理论研究，以及玻璃态聚合物力学领域的教育。 了解聚合物材料（如结构塑料）的强度和失效的工业重要性，使得定量预测其整个机械响应范围成为物理聚合物科学的重要目标。聚合物材料由具有重复化学单元的长链分子组成。 化学性质不同的聚合物表现出显著不同的机械性能;机械响应的巨大差异在确定这些材料的抗断裂稳定性方面起着重要作用。 了解这些不同的机械响应对于开发新的高性能材料以及预测现有系统的故障行为和使用寿命至关重要，但了解它们的进展一直很缓慢。 解释观察到的各种行为仍然是一个悬而未决的问题，微观的，基于物理的模型是迄今为止在预测水平不令人满意。 虽然计算机模拟可以提供关于模型系统变形过程中发生的现象的基本完整的信息，但在缺乏总体理论框架的情况下，对这些信息的物理解释可能是困难的。 最近开发的尚未通过模拟测试的候选框架为变革性进展提供了机会。 这项研究涉及协调建模，将利用这个机会和其他机会，已经出现在最近的实验工作。 该项目长期目标的进展将促进开发可用于从汽车到军备等应用的坚固、轻质结构塑料。 该项目有助于培养两名学生在聚合物物理，统计力学和计算机模拟，并有助于发展现代材料的劳动力。 该奖项还有助于提高代表性不足的少数民族学生，包括非洲裔美国人，西班牙裔和美洲原住民，通过参加美国物理学会桥梁计划获得更高的物理学位。PI计划承担当地桥梁学生招聘，招生和指导的主要责任，以及教授科学技术工程和数学专业发展课程。 PI还将继续制定非认知的招生标准，并努力确保其在桥梁计划和当地应用物理博士课程中的实施。技术总结该职业奖支持计算和理论研究，以及玻璃态聚合物力学领域的教育。 该项目包括一个模拟和分析建模程序，将显着提高聚合物玻璃的机械性能如何与它们的微观相互作用和介观秩序的基本物理理解。 通过改变局部链刚度、样品制备方案和变形历史（包括温度），模拟将系统地将机械响应差异与微观和细观结构差异联系起来。 系统将变形断裂，以确定这些因素如何影响最终的机械性能，如延展性和toughene.The相对较低的计算成本的粗粒度的方法将被用来探索相关的参数空间远比化学详细的模型是可行的。分析工作将补充模拟，并通过迭代过程扩展最近开发的基于微观物理学的聚合物力学理论，其中模拟揭示了理论问题，理论根据需要进行改进，然后用于做出新的预测，这些预测将通过精心设计的后续模拟进行测试。这种组合方法旨在最大限度地促进社区的长期目标，以获得足够的物理理解水平，以开发预测性材料设计原则，以定制机械响应。 该项目长期目标的进展将促进开发可用于从汽车到军备等应用的坚固、轻质结构塑料。 该项目有助于培养两名学生在聚合物物理，统计力学和计算机模拟，并有助于发展现代材料的劳动力。 该奖项还有助于提高代表性不足的少数民族学生，包括非洲裔美国人，西班牙裔和美洲原住民，通过参加美国物理学会桥梁计划获得更高的物理学位。PI计划承担当地桥梁学生招聘，招生和指导的主要责任，以及教授科学技术工程和数学专业发展课程。 PI还将继续制定招生的非认知标准，并努力确保其在桥梁计划和当地应用物理博士课程中的实施。