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：大卫L。McDowell，联合主要研究者：下一代支持耐腐蚀材料设计的模型必须直接包含与纳米尺度上的原子间键合和界面结构相关的信息。 挑战在于开发能够在如此小的尺度下处理行为的方法，但仍然能够在更高的长度尺度下解释结构应用（例如汽车、飞机、网球拍等）中的平均行为的各个方面。该项目将通过链接缺陷分析在纳米级使用原子学（分子动力学）附近的裂纹尖端或在长距离场的平均效应，大量的原子，以实现所谓的界面的行为？粗粮？说明. 通过这种方式，可以在足够高的长度和时间尺度上进行模拟，以提供有关结构行为的有意义的信息，而界面的作用则以原子尺度分辨率进行处理。这项研究预计将大大影响定制晶界结构和细尺度微观结构的能力，从而影响金属合金的疲劳和断裂抗力的改善。 疲劳是经受循环载荷的金属中的失效模式，其导致昂贵的失效，例如公路桥梁、飞机尾部、发动机部件、铁路脱轨和许多其他示例。 通过开发更具预测性的工具来解决原子尺度和多晶体颗粒尺度（通常为五个数量级）之间建模和模拟工具的巨大差距，从更轻质和耐用的材料中获得的节能和安全方面的社会效益可能是巨大的。 研究成果将被整合到计算材料科学的本科课程以及PI和co-PI教授的材料缺陷和机械性能的研究生课程中，加速该项目中开发的技术的应用。

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.