Fatigue Durability and Reliability of Functionally Graded Materials

功能梯度材料的疲劳耐久性和可靠性这一建议的目的是发展基于物理的随机方法的新的理论基础和数值算法，用于预测功能梯度材料的疲劳耐久性和可靠性。建议的工作将基于：(1)用于非均匀微结构随机建模的新的水平截断泊松随机场；(2)用于微观和宏观结构疲劳耐久性分析的新的、计算高效的水平集方法；以及(3)用于随机载荷、材料特性和几何形状的功能梯度材料的二次弯矩和可靠性分析的创新降维方法。从根本上讲，该项目将推进一个很大程度上未知的研究领域，该领域涉及基于物理的、多尺度的、随机的方法，以捕捉真实的微观结构特征、微观和宏观尺度的疲劳损伤以及由此产生的对功能梯度材料随机力学性能的连锁效应。据对PI的最好了解，目前还没有已知的女性生殖器切割的概率模型。因此，该方法的发展是朝着实现更真实的功能梯度材料疲劳耐久性模拟的方向迈出的新的重要一步。所提出的研究将在超高温和大温度梯度下的材料性能和结构完整性评估方面找到许多高科技应用。潜在的应用包括飞机推进中的热障涂层、空间飞行器中的形状记忆合金、高性能弹道部件、快堆核反应堆压力容器、微电子设备、生物工程植入物等。事实上，这里提出的研究将对一些具有国家意义的领域产生积极影响，如民用和军事基础设施、先进材料和信息技术。该项目创造的知识的转让和传播将通过继续与各行业合作、在ASME会议上组织关于女性生殖器切割可靠性的研讨会、同行评议的期刊出版物、在主要会议和机构的演讲和出版物以及学生教育来进行。与两个政府和工业实验室的伙伴关系将使重要的知识和实验数据共享，并实施该项目中开发的基本方法，以解决大规模的工业问题。教育目标包括从少数族裔中招募一名博士生，利用该项目的软件工具升级爱荷华大学主要工程项目的课程，以及编写一本全面的教科书。

FATIGUE DURABILITY AND RELIABILITY OF FUNCTIONALLY GRADED MATERIALSAbstractThe objective of this proposal is to develop new theoretical foundations and numerical algorithms of physics-based stochastic methodology for predicting fatigue durability and reliability of functionally graded materials (FGMs). The proposed effort will be based on: (1) new level-cut Poisson random fields for stochastic modeling of heterogeneous microstructure; (2) new, computationally efficient, level set methods for both micro- and macro-structural fatigue durability analyses; and (3) innovative dimension-reduction methods for second-moment and reliability analyses of FGM subject to random loads, material properties, and geometry. From a fundamental point of view, the project will advance a largely uncharted research area that is concerned with physics-based, multi-scale, stochastic methodology capturing realistic microstructural features, micro- and macro-scale fatigue damage, and resultant cascading effects on stochastic mechanical performance of FGM. To the best knowledge of the PI, no probabilistic models of FGM are known to have been developed. As such, the development of the proposed methodology constitutes a new and significant advance towards the achievement of more realistic fatigue-durability simulation of FGMs.The proposed research will find many high-technology applications involving material performance and structural integrity evaluations under super-high temperatures and large temperature gradients. Potential applications include thermal barrier coating in aircraft propulsion, shape memory alloys in space vehicles, high-performance ballistic components, fast-breeder nuclear reactor pressure vessels, microelectronic devices, bio-engineered implants, and others. Indeed, the research proposed here will positively impact a number of areas of national significance, such as civil and military infrastructure, advanced materials, and information technology. The transfer and dissemination of knowledge created by this project will take place through continued collaboration with industries, organization of symposia on FGM reliability in ASME conferences, peer-reviewed journal publications, presentations and publications at major conferences and institutions, and student education. The partnership with two government and industrial laboratories will enable sharing of important knowledge and experimental data and implementation of the basic methods developed in this project to resolve large-scale industrial problems. The educational goals comprise recruitment of a Ph. D. student from underrepresented minority, implementation of software tools from this project in upgrading courses in The University of Iowa's principal engineering programs, and authoring a comprehensive textbook.