CAREER: A Micromechanics-Based Approach to Ductile Fracture Simulation in Additively Manufactured Steels for Seismic Structural Fuse Design

职业：基于微力学的增材制造钢延性断裂模拟方法，用于抗震结构引信设计

• 批准号: 1751699
• 负责人: Gary Prinz
• 金额: $ 50万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-15 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1751699&HistoricalAwards=false
• 关键词: CAREER; Micromechanics; Based; Approach; Ductile

This Faculty Early Career Development Program (CAREER) award will advance knowledge and innovation to improve the seismic performance of the nation's civil infrastructure through the development of a micro-mechanics based framework for ductile fracture prediction in additively manufactured (AM) steels. Emerging AM technologies, such as 3-D metal printing, are promising for performance-based optimization of seismic steel systems, as they can accommodate highly irregular component designs through highly controlled weld-free geometry formation. In order for AM steel parts to transition to functioning components in seismic structural systems, the ability to predict damage limit states, such as ductile fracture and low-cycle fatigue, is needed. Existing ductile fracture models lack the ability to accurately capture fracture processes in AM steel alloys due to the complex micro features formed during fabrication. This research will develop an innovative framework for upscaling micro-scale material measurements in AM steel alloys to predict macro-scale behavior in seismic structural fuse components. These micro-scale measurements and up-scaling framework can lead to the creation of a hybrid analysis-AM framework, allowing iteration and optimization of seismic structural fuse performance through probabilistic fracture predictions prior to fabrication. The capability to optimize the seismic performance of steel buildings through AM structural fuse design will promote national welfare and prosperity through safer and more resilient and sustainable building construction to better protect life and property during earthquakes and to maintain essential services and business continuities during response and recovery. Integral with this research are an innovative middle school outreach program and a graduate-level international research collaboration with the Swiss Federal Institute of Technology. The middle school outreach, in the form of engineering songwriting workshops, will couple music education with science, technology, engineering, and math (STEM) curricula. Termed STEMusic, the outreach plan aims to promote creativity, understanding, and retention of engineering principles through the engagement of alternative cognitive processes. The international research collaboration will include the exchange of graduate students. The objective of this CAREER award is to test the hypothesis that measured micromechanical material behavior can be scaled to accurately predict macroscale ductile fracture in steel alloys created through common AM processes such as selective laser melting. In the research, modern technologies such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and modified nano-indentation will be used to measure the fundamental localization processes driving ductile fracture in AM steels and create a new simulation framework to allow the future creation of more generalizable fracture models. Steel specimens approximately 0.002 millimeters in diameter will be fabricated using focused ion beam milling and mechanically tested using a modified in-SEM nano-indentation device. The measured micromechanical behavior, coupled with TEM spatial characterizations of the fracture surface microstructure, will be used to inform statistical volume element simulations for upscaling to larger material volumes. This micro-mechanics based framework will be used to investigate the ductile fracture performance of free-form structural fuse geometries (geometries created using AM processes). Potential impacts of this award outside the described application to seismic design include advances in materials engineering and AM fabrication. The micromechanical experiments have the potential to provide fundamental insights into the effects of underlying material morphology and chemistry on macro-mechanical AM steel alloy response, allowing material response (e.g., fracture, yielding, and deformation) to be designed into the AM geometry creation process. Coupling this within the field of nonlinear topology optimization, the framework to be developed will be essential for deriving optimum design solutions that satisfy complex performance criteria involving high plastic strains that lead to fracture or fatigue under various complex loadings.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.

该教师早期职业发展计划（CAREER）奖将通过开发基于微观力学的增材制造（AM）钢延性断裂预测框架来推进知识和创新，以提高国家民用基础设施的抗震性能。新兴的增材制造技术，如3D金属打印，是有希望的抗震钢系统的性能优化，因为它们可以通过高度控制的无焊接几何形状的形成，以适应高度不规则的组件设计。为了使AM钢部件过渡到抗震结构系统中的功能部件，需要预测损伤极限状态的能力，例如延性断裂和低周疲劳。现有的韧性断裂模型缺乏准确捕捉断裂过程中AM钢合金由于在制造过程中形成的复杂的微观特征的能力。这项研究将开发一个创新的框架，用于扩大AM钢合金的微观尺度材料测量，以预测地震结构引信部件的宏观尺度行为。这些微尺度测量和放大框架可以导致创建混合分析AM框架，允许在制造之前通过概率断裂预测来迭代和优化地震结构保险丝性能。通过AM结构保险丝设计优化钢结构建筑抗震性能的能力将通过更安全，更具弹性和可持续性的建筑施工促进国家福利和繁荣，以更好地保护地震期间的生命和财产，并在响应和恢复期间保持基本服务和业务连续性。 与这项研究不可分割的是一个创新的中学推广计划和研究生水平的国际研究合作与瑞士联邦理工学院。 中学推广，在工程歌曲创作研讨会的形式，将音乐教育与科学，技术，工程和数学（干）课程。该推广计划名为STEMusic，旨在通过参与替代认知过程来促进创造力，理解和保留工程原理。 国际研究合作将包括研究生的交流。 该CAREER奖项的目的是测试以下假设：测量的微观力学材料行为可以缩放，以准确预测通过常见AM工艺（如选择性激光熔化）产生的钢合金的宏观韧性断裂。在这项研究中，现代技术，如扫描电子显微镜（SEM），透射电子显微镜（TEM）和改进的纳米压痕将被用来测量驱动AM钢韧性断裂的基本局部化过程，并创建一个新的模拟框架，以允许未来创建更通用的断裂模型。直径约0.002毫米的钢试样将使用聚焦离子束铣削制造，并使用改进的SEM纳米压痕装置进行机械测试。 测得的微观力学行为，再加上TEM的断裂表面微观结构的空间特征，将被用来通知统计体积元模拟放大到更大的材料体积。 这种基于微观力学的框架将用于研究自由形式的结构熔断器几何形状（使用AM工艺创建的几何形状）的韧性断裂性能。该奖项在抗震设计应用之外的潜在影响包括材料工程和AM制造的进步。微观力学实验有可能提供基本的见解，了解基本材料形态和化学对宏观力学AM钢合金响应的影响，允许材料响应（例如，断裂、屈服和变形）设计到AM几何形状创建过程中。耦合在非线性拓扑优化领域内，该框架将是必不可少的，以获得最佳的设计解决方案，满足复杂的性能标准，涉及高塑性应变，导致断裂或疲劳下的各种复杂loading.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

项目成果

Micromechanical Tension Testing of Additively Manufactured 17-4 PH Stainless Steel Specimens

增材制造 17-4 PH 不锈钢试样的微机械张力测试

• DOI: 10.3791/62433
• 发表时间: 2021
• 期刊: Journal of Visualized Experiments
• 作者: Gonzalez-Nino, David;Sonntag, Steven;Afshar-Mohajer, Mahyar;Goss, Josh;Zou, Min;Prinz, Gary S.
• 通讯作者: Prinz, Gary S.

Ultra Low-Cycle Fatigue Behavior Comparison between Additively Manufactured and Rolled 17-4 PH (AISI 630) Stainless Steels

• DOI: 10.3390/met11111726
• 发表时间: 2021-10
• 期刊: Metals
• 影响因子: 2.9
• 作者: David Gonzalez-Nino;Timothy Strasser;G. Prinz