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.

非技术摘要该奖项支持旨在识别和量化金属材料疲劳损伤机械驱动因素的研究和教育活动。疲劳是与晶体材料在连续和重复施加载荷下失效相关的物理过程。对于防止机械、设备和结构中的金属结构部件失效具有巨大价值。准确预测疲劳寿命需要了解微观尺度（裂纹产生的尺度）裂纹萌生的控制机械驱动因素。然而，由于金属材料裂纹萌生部位附近的微观结构随着载荷的变化而不断变化，因此识别这些机械驱动因素是一项具有挑战性的任务，在该项目中，PI 将采用集成的计算和实验方法来应对这一挑战。该项目的主要重点将是具有非常大晶粒的纯金属，例如镍，从研究中获得的见解和工具将提高各种疲劳寿命预测的准确性。大颗粒金属的该项目将支持数据密集型材料研究领域多样化的未来劳动力的教育和培训，以激励中学生攻读材料科学和工程学位。制定简短、适合年龄的讲座，解释学生的基础课堂学习如何与专业工程师使用的实际工具和模型相关，并让学生有机会使用这些工具进行非常基本的模拟。技术摘要该奖项支持研究和教育活动识别和量化具有高堆垛层错能的粗晶面心立方材料中疲劳裂纹形核的微观机械驱动力指标具有挑战性，因为在晶体材料附近存在诸如持久滑移带及其相互作用等微观结构特征。裂纹萌生位置随着循环载荷的变化而不断演变，从而产生复杂的微机械场和相互作用，这使得确定裂纹萌生的控制机制驱动因素变得困难，这项工作的具体目标包括：（1）确定如何产生裂纹。应变局部化影响循环加载期间的表面变形；(2) 建立对地下变形机械驱动因素的统一理解；(3) 研究应变局部化作为裂纹萌生前兆的微观结构和微观机械原理，(4) 确定其影响这将通过综合计算和实验方法来实现。从研究中获得的见解和工具将提高疲劳寿命预测的准确性。此外，该项目还将支持数据密集型材料研究领域的多样化未来劳动力的教育和培训，以激励中学生对材料的研究。科学和工程学位时，PI 将制作简短、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相关，并让学生有机会使用这些工具执行非常基本的模拟。该奖项反映了 NSF 的法定使命通过使用基金会的智力优点和更广泛的影响审查标准进行评估，并被认为值得支持。