Atomistic Simulation Based Crack Evolution Models for Crystal Plasticity FEM of Crystalline Metals

基于原子模拟的晶体金属晶体塑性有限元裂纹演化模型

• 批准号: 1200231
• 负责人: Somnath Ghosh
• 金额: $ 30.2万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1200231&HistoricalAwards=false
• 关键词: Atomistic; Simulation; Based; Crack; Evolution

The research objective of this grant is the development of physics-based crack evolution models in polycrystalline metallic materials for use in crystal plasticity finite element models. The unified deformation-fracture models will be developed by upscaling variables from atomic-scale, molecular dynamics simulations with explicit depiction of the atomic structure and deformation mechanisms. Upscaling will provide a framework for cohesive laws and associated evolution laws for deformation variables along specific slip systems. A systematic approach will be undertaken, encompassing the following tasks: (i) molecular dynamics (MD) simulations of 3D crystalline lattice systems to simulate the evolution of ductile and brittle crack evolution under a variety of force fields, (ii) development of accelerated MD methods to simulate longer time scales consistent with experiments, (iii) characterization and identification of crack tip deformation mechanisms, followed by quantification of the local atomic structure and evolution, and (iv) development of energy-based laws governing crack growth in the process zone by partitioning the total energy corresponding to different physical mechanisms.Benefits to the scientific community will be accomplished through the establishment of novel crack evolution models of critical importance in analysis and design of materials for better fracture toughness and ductility. Advancement in accelerated molecular dynamics modeling will allow modeling at strain rates of realistic experiments. Collaboration with Sandia and Brown Deer Technology will enable technology transfer of deliverables for broader utilization. Students will have strong interactions with eminent researchers at Sandia National Laboratories and a small-scale development company to see the direct impact of their work.

该赠款的研究目标是在多晶金属材料中开发基于物理的裂纹演化模型，用于晶体可塑性有限元模型。 统一的变形 - 骨折模型将通过从原子尺度的分子动力学模拟中提出的变量来开发，并明确描绘原子结构和变形机制。 升级将为沿特定滑移系统的变形变量提供粘性定律和相关的演化定律的框架。 将采用一种系统的方法，包括以下任务：（i）3D晶格系统的分子动力学（MD）模拟，以模拟在各种力场下的延性和脆性裂纹演变的演变，（ii）加速MD的发展模拟与实验相一致的较长时间尺度的方法（iii）表征和识别裂纹尖端变形机制，然后定量局部原子结构和进化，以及（iv）制定基于能量的法律，该法律管理过程区域的裂纹生长通过分配与不同物理机制相对应的总能量。科学界的屈服将通过在分析和设计材料的分析和设计方面建立新颖的裂纹演化模型来实现，从而获得更好的断裂韧性和延展性。 加速分子动力学建模的进步将允许以实际实验的应变速率进行建模。 与Sandia和Brown Deer Technology的合作将使可交付成果的技术转移以进行更广泛的利用。 学生将与桑迪亚国家实验室的著名研究人员和一家小规模开发公司进行牢固的互动，以查看其工作的直接影响。