Collaborative Research: Accelerated Large-Scale Simulation Study of Atomic-Scale Wear Using Hyper-Quasicontinum

合作研究：使用超准连续加速原子尺度磨损的大规模模拟研究

• 批准号: 1462807
• 负责人: Ellad Tadmor
• 金额: $ 24.84万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1462807&HistoricalAwards=false
• 关键词: Collaborative; Research; Accelerated; Large; Scale

This collaborative award supports research on the mechanics of wear mechanisms occurring at the atomic scale. A novel predictive computational approach, the hyper-quasicontinuum (hyper-qc) method, will be employed and advanced. This approach will enable the computational simulation of friction and wear at realistic sliding speeds with atomic resolution of critical events and spatial domains. The simulation results are expected to lead to new insights into the fundamentals of atomic-scale wear. Such knowledge is a prerequisite for predicting wear at macroscopic length scales. Hence the outcomes will provide valuable insight into the improved engineering of structures and materials with the aim of wear reduction. Wear of conventional mechanical parts has been conservatively estimated to cause a loss equivalent to approximately 1.5 percent of an industrialized nation's Gross Domestic Product. For the United States, this corresponds to about 250 billion dollars in 2013. The problems arising from wear are even more critical in the newly emerging field of nanotechnology. Wear significantly hampers the adoption of systems with moving parts. Thus, the outcomes would enable further advances in nanotechnology. All computer codes established as an outcome of this project will be made freely available to the research community via dedicated web portals (qcmethod.org and openkim.org). The collaborative project will provide training for graduate students. An outreach program for science and engineering education will be organized with local high schools in Cincinnati whose student populations are predominantly from underrepresented groups. The ultimate aim of this project is to develop a novel predictive model for nano-scale wear, which can be used to reduce wear at macroscopic length scales. The research approach is based on the use of the hyper-qc method. To enable the analysis of wear, methodological innovations to advance the hyper-qc method are necessary. These advances would enable the method to deal with multiple time-scales. A novel approach for coupling of atomistic and continuum regions accounting for heat transfer will also be established. The hyper-qc method will make it possible to consider key experiments on atomic-scale wear. Simulating will capture all relevant features of wear experiments with an atomic force microscope apparatus. Thereby, atomic resolution is retained in the contact region and sliding speeds comparable to actual experiments are considered. Wear simulations will consider various engineering materials of technological interest including silicon, silicon-oxides, and diamond-like carbons. From the hyper-qc simulations it will be possible to identify the atomic-scale mechanisms responsible for wear at the nano-scale and to study their dependence on important experimental conditions such as sliding velocity and temperature. Conflicts between simulation results and experimental data and observations will be used to improve existing models for nano-scale wear.

该合作奖项支持对原子尺度磨损机制的研究。将采用和改进一种新颖的预测计算方法，即超准连续谱（hyper-qc）方法。这种方法将能够以实际滑动速度对摩擦和磨损进行计算模拟，并具有关键事件和空间域的原子分辨率。模拟结果预计将为原子尺度磨损的基本原理带来新的见解。这些知识是预测宏观长度尺度磨损的先决条件。因此，研究结果将为改进结构和材料工程提供有价值的见解，以减少磨损。保守估计，传统机械零件的磨损造成的损失相当于工业化国家国内生产总值的约 1.5%。对于美国来说，这相当于2013年约2500亿美元。磨损引起的问题在新兴的纳米技术领域更为严重。磨损严重阻碍了带有移动部件的系统的采用。因此，这些成果将推动纳米技术的进一步进步。作为该项目成果而建立的所有计算机代码将通过专门的门户网站（qcmethod.org 和 openkim.org）免费提供给研究界。该合作项目将为研究生提供培训。将与辛辛那提当地高中一起组织科学和工程教育的外展计划，这些高中的学生群体主要来自代表性不足的群体。该项目的最终目标是开发一种新颖的纳米级磨损预测模型，可用于减少宏观长度尺度的磨损。该研究方法基于超质量控制方法的使用。为了实现磨损分析，需要进行方法创新来推进超级质量控制方法。这些进步将使该方法能够处理多个时间尺度。还将建立一种耦合原子区域和连续区域以解释传热的新方法。超质量控制方法将使考虑原子尺度磨损的关键实验成为可能。模拟将使用原子力显微镜设备捕获磨损实验的所有相关特征。因此，在接触区域保留了原子分辨率，并且考虑了与实际实验相当的滑动速度。磨损模拟将考虑各种具有技术意义的工程材料，包括硅、硅氧化物和类金刚石碳。通过超质量控制模拟，将有可能识别导致纳米尺度磨损的原子尺度机制，并研究它们对滑动速度和温度等重要实验条件的依赖性。模拟结果与实验数据和观察结果之间的冲突将用于改进现有的纳米级磨损模型。