Determining the Driving Force for Fatigue Crack Nucleation in a Superelastic Nickel Titanium Shape Memory Alloy

确定超弹性镍钛形状记忆合金疲劳裂纹形核的驱动力

• 批准号: 1934753
• 负责人: John Moore
• 金额: $ 44.8万
• 依托单位: Marquette University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1934753&HistoricalAwards=false
• 关键词: Determining; Driving; Force; Fatigue; Crack

The fatigue life of a material is the number of load cycles it can withstand before breaking; for example, the fatigue life of a straightened paperclip is the number of times it can be bent back-and-forth before it breaks. Aircrafts, automobiles, and biomedical devices are prone to such failures, yet many of the mechanisms that govern fatigue life are poorly understood. This understanding is especially limited for Nickel-Titanium alloys, which are used in such varied applications as biomedical devices and Mars rover tires. This award supports research into the cause of fatigue crack formation which eventually leads to material failure in a Nickel-Titanium material and will create a design tool for enhancing fatigue life. The result will benefit the healthcare field by increasing the robustness of artificial heart valves, stents, and other minimally invasive biomedical devices, therefore decreasing patient trauma and healthcare costs. This project also exposes graduate students to high-performance computing and Argonne National Laboratory's Advanced Photon Source. Skills gained at the Advanced Photon Source will position the student to contribute to national energy and defense needs. High-performance computing training will expand a workforce focused on big-data, machine learning, and artificial intelligence. Additionally, this project will familiarize students with engineering vocabulary by producing a video about fatigue that is intended to reduce barriers for first generation engineers and improve engineering education.Superelastic Nickel-Titanium elastically recovers from large deformations and thus is ideal for minimally invasive biomedical devices and other applications such as Mars rover tires. However, due to microscale defects, Nickel-Titanium is prone to cyclic fatigue cracking. This project builds a crystal plasticity model of Nickel-Titanium and measures crack nucleation around a defect using X-ray micro-tomography and high energy diffraction microscopy. The measured defect geometry is then combined with the model to predict the plastic strain around the measured fatigue crack. Plastic strain plays a key role in fatigue crack nucleation but is difficult to measure; thus, a crystal plasticity model will be used. A data-driven procedure will automate the generation of a fatigue indicator parameter that predicts the mechanical state driving crack nucleation. Fatigue indicator parameters are a commonly proposed tool in the computational design of materials for fatigue resistance; however, current fatigue indicator parameters suffer from inaccuracies, which this project addresses. The projects outcomes are a validated fatigue indicator parameter-based modeling paradigm and a transformative design tool for the development of fatigue resistant superelastic Nickel-Titanium materials.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.

材料的疲劳寿命是指其断裂前能够承受的载荷循环次数；例如，拉直的回形针的疲劳寿命是指它在断裂之前可以来回弯曲的次数。飞机、汽车和生物医学设备很容易出现此类故障，但人们对许多控制疲劳寿命的机制知之甚少。这种理解对于镍钛合金尤其有限，镍钛合金用于生物医学设备和火星车轮胎等各种应用。该奖项支持对疲劳裂纹形成原因的研究，最终导致镍钛材料失效，并将创建一种提高疲劳寿命的设计工具。该结果将通过提高人造心脏瓣膜、支架和其他微创生物医学设备的坚固性，从而减少患者创伤和医疗成本，从而使医疗保健领域受益。该项目还让研究生接触高性能计算和阿贡国家实验室的高级光子源。在高级光子源中获得的技能将使学生能够为国家能源和国防需求做出贡献。高性能计算培训将扩大专注于大数据、机器学习和人工智能的劳动力队伍。此外，该项目将通过制作有关疲劳的视频来帮助学生熟悉工程词汇，旨在减少第一代工程师的障碍并改善工程教育。超弹性镍钛合金可以从大变形中弹性恢复，因此非常适合微创生物医学设备和其他应用，例如火星车轮胎。然而，由于存在微观缺陷，镍钛合金很容易出现循环疲劳裂纹。该项目建立了镍钛晶体塑性模型，并使用 X 射线显微断层扫描和高能衍射显微镜测量缺陷周围的裂纹成核。然后将测量的缺陷几何形状与模型相结合，以预测测量的疲劳裂纹周围的塑性应变。塑性应变在疲劳裂纹形核中起着关键作用，但难以测量；因此，将使用晶体塑性模型。数据驱动的程序将自动生成疲劳指示参数，该参数可预测驱动裂纹形核的机械状态。疲劳指标参数是抗疲劳材料计算设计中常用的工具；然而，当前的疲劳指标参数存在不准确的问题，本项目解决了这一问题。该项目的成果是经过验证的基于参数的疲劳指标建模范式和用于开发抗疲劳超弹性镍钛材料的变革性设计工具。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值进行评估，被认为值得支持以及更广泛的影响审查标准。

项目成果

Effects of martensitic phase transformation on fatigue indicator parameters determined by a crystal plasticity model

• DOI: 10.1016/j.ijfatigue.2022.107457
• 发表时间: 2022-12
• 期刊: International Journal of Fatigue
• 影响因子: 6
• 作者: J. A. Moore;Jacob P. Rusch;Parisa Shabani Nezhad;S. Manchiraju;Dinc Erdeniz