Collaborative Research: An Integrated Multiscale Modeling and Experimental Approach to High Cycle Fatigue Life Prediction

这个合作项目的研究目标是用紧密集成的建模/实验方法研究具有代表性的工程合金(304奥氏体不锈钢、Inconel718+Ni基高温合金和Ti-6Al-4V合金)的高周疲劳破坏。建立了基于丰富的时空有限元方法和多尺度疲劳损伤模型的计算框架。通过这种方法，将通过对关键因素的研究获得新的知识，如载荷循环、应力历史和三轴性、载荷之间的非线性耦合以及复杂的几何形状，这些都是已知的对疲劳破坏具有关键影响的因素，通常在目前的经验设计方法中并未完全考虑到这些因素。通过计算揭示的基本机制将通过现有的实验数据以及拟议的高周疲劳试验进行验证和验证，这些试验具有现场监测疲劳裂纹萌生和扩展的特点。此外，还将进行微观结构表征，以建立观察到的微观结构变形机制与所提出的多尺度材料模型之间的映射。如果成功，该项目将为许多关键工程应用中控制高周疲劳破坏的基本机制带来新的夜晚。例子包括用于能源和电力应用的涡轮机、航空航天结构部件和高性能电子产品。由该项目开发的多尺度模拟模型和实验技术也将对其他正在研究更广泛的材料和器件的高周疲劳机理的研究人员感兴趣。已获得的高周疲劳专题研究成果将全面纳入本科生/研究生课程。通过利用网络手段，这些知识将通过各种渠道传播给广泛的受众，包括毕业生、本科生、K-12和代表性不足的群体。

The research objective of this collaborative project is to investigate high cycle fatigue failure in representative engineering alloys (304 austenitic stainless steel, Inconel 718+ Ni-based superalloy and Ti-6Al-4V alloy) with a tightly integrated modeling/experimental approach. A computational framework will be established based on the integration of an enriched space-time finite element method and a multiscale fatigue damage model. With this approach, new knowledge will be gained through studies on key factors such as load cycles, stress history and triaxiality, nonlinear coupling among the loads, and complex geometry, which are known to critically influence the fatigue failure and generally not fully accounted for in the empirical design approaches that are being practiced today. The fundamental mechanisms revealed through the computational efforts will be verified and validated through existing experimental data as well as proposed high cycle fatigue tests featuring in-situ monitoring of fatigue crack initiation and propagation. Additionally, microstructural characterization will be performed to establish a map between the observed microstructural deformation mechanism and the proposed multiscale material model.If successful, this project will shed new night on the fundamental mechanisms that govern the high cycle fatigue failure in many critical engineering applications. Examples include turbines used for energy and power applications, aerospace structural components, and high-performance electronics. The multiscale simulation models and experimental techniques developed from this project will also be of interest to other researchers who are studying high cycle fatigue mechanism for a broader range of materials and devices. The acquired research results on the topic of high cycle fatigue will be fully incorporated into the undergraduate/graduate curricula. With a cyber-enabled approach, the knowledge will be disseminated through a variety of channels towards a wide range of audiences, including graduates, undergraduates, K-12 and underrepresented groups.