Multimodal and Multiscale-driven Quantification of Micromechanical Metrics for Location-specific Fatigue Microcracking

特定位置疲劳微裂纹的多模态和多尺度驱动的微机械指标量化

基本信息

批准号：
2152369
负责人：
Leslie Mushongera
金额：
$ 24.27万
依托单位：
Board of Regents, NSHE, obo University of Nevada, Reno
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2025-07-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2152369&HistoricalAwards=false
关键词：
Multimodal Multiscale driven Quantification Micromechanical

项目摘要

NONTECHNICAL SUMMARYThis award supports research and education activities aimed at identifying and quantifying the mechanistic drivers for fatigue damage in metallic materials. Fatigue is a physical process that is associated with the failure of crystalline materials under continuous and repeated application of loads. The knowledge of fatigue is of immense value in preventing the failure of metallic structural components in machinery, equipment and structures. The accurate prediction of fatigue life requires the need to know the governing mechanistic drivers for crack initiation at the microscale (the scale at which cracks initiate). However, since the microstructure in the vicinity of the crack initiation sites in metallic materials evolves continuously with loading, the identification of these mechanistic drivers is a challenging task. In this project, the PI will address this challenge with an integrated computational and experimental approach that will provide a deeper understanding of the factors influencing fatigue crack initiation. The primary focus of the project will be on pure metals with very large grains such as nickel. Insights and tools obtained from the research will improve the accuracy of fatigue life predictions for a variety of large-grained metallic structural components and thin film devices that undergo cyclic stresses. Additionally, the project will support the education and training of a diverse future workforce in data-intensive materials research. To inspire middle and high school students to pursue materials science and engineering degrees, the PI will develop brief, age-appropriate lectures that explain how students’ basic classroom learning relates to the actual tools and models that professional engineers use and give the students the chance to perform very basic simulations using the tools.TECHNICAL SUMMARYThis award supports research and education activities to identify and quantify the micromechanical driving force metrics for fatigue crack nucleation in coarse-grained face centered cubic materials with a high stacking fault energy. Understanding fatigue damage in crystalline materials is challenging because the microstructural features such as persistent slip bands and their interactions, in the vicinity of the crack initiation sites evolve continuously with cyclic loading. The continuous evolution of the microstructure generates complex micromechanical fields and interactions which makes it difficult to pinpoint the governing mechanistic drivers for crack initiation. Specific goals of this work include: (1) identify how strain localization affects the surface deformation during cyclic loading; (2) establish a unifying understanding of mechanistic drivers for subsurface deformation; (3) investigate the microstructural and micromechanical rationale for strain localization as a precursor to crack initiation and, (4) identify the influence of high strain gradients on microcracking at persistent slip band-matrix interfaces. This will be achieved through an integrated computational and experimental approach.Insights and tools obtained from the research will improve the accuracy of fatigue life predictions for a variety of large-grained metallic structural components and thin film devices that undergo cyclic stresses. Additionally, the project will support the education and training of a diverse future workforce in data-intensive materials research. To inspire middle and high school students to pursue materials science and engineering degrees, the PI will develop brief, age-appropriate lectures that explain how students’ basic classroom learning relates to the actual tools and models that professional engineers use and give the students the chance to perform very basic simulations using the tools.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要这一奖项支持旨在识别和量化金属材料疲劳损害的机械驱动因素的研究和教育活动。疲劳是一个物理过程，它与在载荷的连续和重复应用下晶体材料的失败有关。疲劳的知识在防止机械，设备和结构中金属结构组件的失败方面具有巨大的价值。疲劳寿命的准确性预测需要知道在微观上的机械驱动器进行裂纹倡议（裂纹启动的规模）。但是，由于金属材料中裂纹启动位点附近的微观结构随着负载不断发展，因此这些机械驱动器的识别是一项挑战任务。在该项目中，PI将通过集成的计算和实验方法来应对这一挑战，该方法将对影响疲劳裂纹倡议的因素有更深入的了解。该项目的主要重点将放在具有非常大谷物（例如镍）的纯金属上。从研究中获得的洞察力和工具将提高疲劳寿命预测的准确性，这些预测对于各种经历环状应力的大粒金属结构组件和薄膜设备。此外，该项目将支持在数据密集型材料研究中对潜水员未来劳动力的教育和培训。 To encourage middle and high school students to purchase materials science and engineering degrees, the PI will develop brief, age-appropriate lectures that explain how students’ basic classroom learning relates to the actual tools and models that professional engineers use and give the students the chance to perform very basic simulations using the tools.TECHNICAL SUMMARYThis award supports research and education activities to identify and quantify the micromechanical driving force metrics for fatigue crack nucleation in coarse-grained face centered具有高堆叠断层能量的立方体材料。挑战了晶体材料中的疲劳损伤，因为在裂纹启动部位附近的微观结构特征，例如持续的滑移带及其相互作用，随着环状载荷的连续发展。微观结构的连续演变产生了复杂的微机械场和相互作用，这使得很难确定处理机械驱动程序的裂纹启动。这项工作的特定目标包括：（1）确定应变定位如何影响循环载荷过程中的表面变形；（2）建立对地下变形的机械驱动器的统一理解；（3）研究了应变定位的微观结构和微观机械基本原理，作为裂纹主动性的先驱，（4）确定高应变梯度对在持久滑移带矩阵接口处微裂纹的影响。从研究中获得的投影和工具将通过综合的计算和实验方法实现，这将提高疲劳寿命预测的准确性，用于各种大颗粒的金属结构组件和经历环状应力的薄膜设备。此外，该项目将支持在数据密集型材料研究中对潜水员未来劳动力的教育和培训。为了激发中学生和高中生纯化材料科学和工程学位，PI将开发简短的，适合年龄的讲座，解释学生的基本课堂学习如何与专业工程师使用的实际工具和模型有关，并使学生有机会使用该工具进行非常基本的模拟，以表达NSF的法定任务和良好的依据，这是通过评估良好的依据来评估的。