Multiresolution, Coarse-Grained Modeling of 3D Dislocation Nucleation and Migration

CMMI 0758265三维位错成核和迁移的多分辨率、粗粒度建模PI：David L.McDowell，Co-PI：Ting朱下一代模型支持抗断裂材料的设计必须直接纳入与纳米尺度的原子间键合和界面结构相关的信息。所面临的挑战是开发一种方法，既能解决如此小尺度的行为，又能在汽车、飞机、网球拍等结构应用中考虑更高长度尺度下的平均行为的方面。这个项目将通过在纳米尺度上使用原子学(分子动力学)在裂纹尖端附近或在长程场的界面上分析缺陷来解决这种行为，这些长程场平均大量原子的影响，以实现所谓的？粗晶？描述。通过这种方式，可以在足够长和足够长的时间尺度上进行模拟，以提供关于结构行为的有意义的信息，而界面的作用是以原子尺度的分辨率来处理的。这项研究有望显著影响定制晶界结构和精细尺度微结构的能力，从而影响金属合金的疲劳和断裂抗力的提高。疲劳是金属在循环载荷下的一种失效模式，它导致了代价高昂的失效，如公路桥、飞机尾部、发动机部件、铁路脱轨和许多其他例子。通过开发更具预测性的工具来解决多晶体中原子尺度和颗粒尺度(通常为五个数量级)之间的建模和模拟工具之间的巨大差距，从更轻和更耐用的材料获得的节能和安全方面的社会好处可以是巨大的。研究成果将被整合到计算材料科学的本科课程以及由PI和Co-PI教授的关于材料缺陷和力学性能的研究生课程中，加速该项目开发的技术的应用。

CMMI 0758265Multiresolution, Coarse-Grained Modeling of 3D Dislocation Nucleation and MigrationPI: David L. McDowell, Co-PI: Ting ZhuNext generation models to support design of fracture-resistant materials must directly incorporate information related to interatomic bonding and structure of interfaces at nanoscales. The challenge is to develop methods that can address behavior at such small scales yet still account for aspects of average behavior at much higher length scales in structural applications such as automobiles, aircraft, tennis rackets, and so forth. This project will address behavior by linking defects analyzed at the nanoscale using atomistics (molecular dynamics) near the tips of cracks or at interfaces with long range fields that average effects of large numbers of atoms to achieve a so-called ?coarse grain? description. In this way, simulations can be undertaken at high enough length and time scales to provide meaningful information regarding behavior of structures, while the role of interfaces is treated with atomic-scale resolution.This research is expected to substantially impact the ability to tailor the structure of grain boundaries and fine scale microstructure to affect improved fatigue and fracture resistance of metal alloys. Fatigue is a failure mode in metals subjected to cyclic loading that is responsible for costly failures such as highway bridges, airplane tail sections, engine components, railway derailments, and many other examples. By developing more predictive tools to address the large gap in modeling and simulation tools between atomic scales and scales of grains in polycrystals (typically five orders of magnitude), the societal benefits in terms of energy savings and safety derived from more lightweight and durable materials can be substantial. Research results will be integrated into both an undergraduate course in computational materials science as well as graduate courses in defects and mechanical properties of materials taught by the PI and co-PI, accelerating the application of the technology developed in this project.