Significant Enhancement of Structural Integrity of Shape Memory Ceramics in High Cycle Fatigue

形状记忆陶瓷在高周疲劳中的结构完整性显着增强

基本信息

批准号：
2054274
负责人：
Cristian Ciobanu
金额：
$ 39.05万
依托单位：
Colorado School of Mines
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2025-08-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2054274&HistoricalAwards=false
关键词：
Significant Enhancement Structural Integrity Shape

项目摘要

Although shape memory ceramics have shown good performance in low cycle fatigue, their significant deterioration in high cycle fatigue has stalled their applications. This award supports fundamental research to understand the mechanisms of nano and microscale fracture in shape memory ceramics and to study how engineered defects can impede facture under high cycle fatigue. These new scientific insights are important for the development and use of shape memory ceramics in applications requiring high-temperature and corrosion-resistant actuators and may propel the U.S. into the forefront of advanced shape memory ceramic technology. The award will provide training and education at several levels: a graduate student and a postdoctoral research associate will be recruited to perform the research, supported by undergraduate research interns, and K-12 students will be introduced to concepts in advanced computational research. Lastly, a professional development course for graduate students will be further developed and the research will be integrated in a core graduate-level course on computational mechanics.Fracture in high cycle fatigue has been one of the main drawbacks of shape memory ceramics. Until now, most efforts have focused on eliminating defect structures in the manufacturing of these ceramics to enable their use in applications that do not take advantage of the shape memory effect. Matristic phase transformation that mediates the thermo-mechanical shape memory behavior of ceramics is associated with a nanoscale volume expansion aiding the nanoscale fracture. This research will fundamentally study how engineering defects into the nano and microstructures of shape memory ceramics can accommodate the volume expansion and mitigate both interface and grain boundary fracture and unwanted amorphous phase formation during high cycle fatigue. The mechanisms of nanoscale cracking during the first few fatigue cycles will be studied by petascale atomistic simulations. And at the microscale, the effects of engineered defects on high cycle fatigue fracture will be studied by coupling the physics and thermodynamics of shape memory behavior in ceramics with those of the fatigue and fracture under a phase field modeling framework. Verification and validation of models and simulation data along with uncertainty quantification will be done with experimental data available in the literature. The findings will be used to propose new fatigue lifetime prediction functions that account for the volume fraction and size of the defects and other nano and microstructural features.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.

尽管形状的记忆陶瓷在低周期疲劳中表现出良好的性能，但它们在高周期疲劳中的显着恶化已经停滞不前。该奖项支持基本研究，以了解形状记忆陶瓷中纳米和微观裂缝的机制，并研究工程缺陷如何在高周期疲劳下妨碍构成构成的构造。这些新的科学见解对于在需要高温和耐腐蚀的执行器的应用中开发和使用形状记忆陶瓷很重要，并可能使美国成为先进形状记忆陶瓷技术的最前沿。该奖项将在多个层面提供培训和教育：研究生和博士后研究助理将在本科研究实习生的支持下进行研究，并将K-12学生介绍高级计算研究的概念。最后，将进一步开发针对研究生的专业发展课程，该研究将集成到核心研究生级课程中。《高周期疲劳》中的杂物一直是形状记忆陶瓷的主要缺点之一。到目前为止，大多数努力都集中在消除这些陶瓷制造中的缺陷结构上，以使其在不利用形状记忆效应的应用中使用。介导陶瓷的热机械形状记忆行为的母阶相变与纳米级体积扩展有助于纳米级骨折。这项研究将从根本上研究如何在高周期疲劳期间，工程缺陷如何纳入纳米和形状记忆陶瓷的微观结构可以适应体积膨胀并减轻界面和晶界断裂以及不需要的无定形相形成。 Petascale原子模拟将研究前几个疲劳周期中纳米级破裂的机制。在微观上，将通过将陶瓷中形状记忆行为的物理和热力学以及在相位场上建模框架下的疲劳和裂缝的物理学和热力学结合，研究工程缺陷对高周期疲劳骨折的影响。文献中可用的实验数据将对模型和仿真数据以及不确定性量化进行验证和验证。这些发现将用于提出新的疲劳终身预测功能，以说明缺陷的数量和大小以及其他纳米和微观结构功能。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点通过评估来支持的。和更广泛的影响审查标准。