纳米孪晶材料塑性及断裂力学行为数值模拟与理论研究

The current project of the Young Scientists Fund supported by NSFC mainly focuses on the development of multiscale simulation method for and multiscale analysis of mechanical behaviors of materials. During the execution of the project, we studied the coupling technique for molecular dynamics and finite element methods, developed basic computer codes for these two methods and their coupling method. We also carried out theoretical/numerical analysis of one-dimensional nanostructured materials and multiscale analysis of the transport behavior of fluid confined in nanochannel, proposed multiscale coarse-grained model for the simulation of golden nanoparticles in biological environment and a new kind of multiscale finite element method for the mechanical analysis of liquid cell materials. Based on the results of these studies, 12 scientific papers have been published on several well-known journals for computational mechanics and related disciplines, among which 12 and 11 papers have been indexed by SCI and EI, respectively, and 6 papers been published in journals with impact factor larger than 3.0. In addition, our works have attracted much attention and many papers have been cited positively by researchers. Until now, these papers have attracted 30 times of citation by SCI-indexed papers. Based on the atomistic, continuum and coupled analysis methods developed during the project of the Young Scientists Fund, this proposed project will focus on the numerical and theoretical study of plastic deformation and fracture behavior of nanotwinned materials. That is, the project will develop reliable methods for the generation of the simulation model of nanotwinned materials, study the plastic deformation and fracture behaviors of these materials, try to find out the underlying physical and mechanical mechanisms and construct theoretical models on the yield and fracture strengths. The outcomes of the project will provide basic information for tailoring the material microstructures and for the fabrication and application of new nanotwinned materials with high strength and good ductility.

青年基金项目主要围绕材料力学行为的多尺度模拟方法和多尺度分析开展研究工作，主要研究了耦合分子动力学-有限元多尺度计算方法、初步研发了分子动力学和有限元及其耦合程序、开展了一维纳米材料力学行为的理论模型研究及数值分析、纳米通道流体流动行为多尺度分析、生物环境中的金纳米粒子力学行为多尺度分析以及多尺度有限元方法研究。相关研究成果在计算力学及其交叉领域的国内外重要学术期刊上发表论文12篇（其中SCI收录12篇，EI收录11篇，影响因子3.0以上6篇），相关研究成果得到了国内外同行的关注与正面引用，截止目前SCI他引30次。本项目将在已有研究工作的基础上进一步开展纳米孪晶材料塑性及断裂力学行为研究，发展纳米孪晶材料基本模型生成算法，揭示材料的塑性变形及断裂机理，建立可用于纳米孪晶材料的尺寸和应变速率关联理论模型，为优化材料微结构，制备和应用高强高韧纳米晶体材料提供理论依据。

本项目围绕纳米孪晶材料塑性及断裂力学行为数值模拟与理论研究开展工作。针对纳米多晶材料微结构演化分析LBM方法、五重孪晶金属纳米线弹性性质与塑性变形行为、孪晶材料中位错与孪晶界的本征相互作用、含缺陷纳米孪晶材料的塑性变形机理、复杂纳米孪晶材料塑性变形行为与机理以及纳米孪晶材料疲劳裂纹扩展行为开展了深入研究，揭示了孪晶材料塑性变形行为和机理、裂纹扩展特征和规律，为优化材料微结构，制备和应用高强高韧纳米晶体材料提供了理论依据。基于项目研究工作，共发表学术期刊论文15篇，其中SCI收录14篇；项目执行期间项目成员积极开展国际合作交流，赴澳大利亚、新加坡、西班牙、英国、韩国等地参加了国际会议7次、国内会议1次，团队成员作学术报告7次，包括项目负责人作国际会议邀请报告1次、专题研讨会Keynote报告2次；执行期间项目负责人入选教育部新世纪优秀人才支持计划（2013年）、获ICACM Young Investigator Award（2013年）和杜庆华工程计算方法优秀青年学者奖（2015年）；此外培养毕业硕士4人，在读博士3人、硕士1人；培养的研究生获得博士研究生国家奖学金及钱令希力学奖学金等荣誉。