MRI: Acquisition of an X-Ray Micro-Computed Tomography System for Evaluating Crack Evolution and Failure Characterization of Engineering Materials

该主要研究仪器（MRI）的目标是开发一种高能和高分辨率的x射线断层扫描系统，用于对密歇根大学迪尔伯恩分校（UM-D）工程材料的裂纹扩展和失效进行无损微观结构评估。该系统将构成一个基础设施，以支持正在进行的多学科制造相关研究活动，包括裂纹起裂和扩展的精确测量、工程结构的质量检查或损伤评估、与裂纹扩展相关的失效机制、与微尺度和中尺度损伤演变相关的连续损伤机制、疲劳损伤和汽车工业中使用的工程材料的可成形性。这些研究的主要目标是发展一种能够准确确定工程材料微观结构损伤演变和/或破坏机制的无损方法，提供微观/中观和宏观尺度损伤机制之间的关键联系，并通过提出的测量系统开发用于工程结构损伤评估的创新算法。目前的研究成果将导致：1)在不需要卸载和解剖材料试样的情况下，通过测量和分析完整和连续加载过程中空间微/中尺度裂纹扩展，在理解工程材料破坏过程中的损伤演化过程中有潜在的突破；2)微/中尺度裂纹扩展模式与损伤力学的可能结合；3)利用空间断裂裂纹特征为服役条件下工程结构的损伤评估和剩余寿命预测提供了一种准确的方法。提出的无损测量系统将大大加强澳大的研究基础设施，并将通过本科生设计项目和研究培训显著提高澳大的教育质量。社区外展活动将激发高中生对科学和工程的兴趣，并扩大迪尔伯恩和底特律社区中代表性不足的黑人少数族裔和女学生的参与。

The objective of this Major Research Instrumentation (MRI) is to develop the acquisition of a high-energy and high-resolution X-ray tomography system for the nondestructive microstructural evaluation of crack propagation and failure of engineering materials at the University of Michigan, Dearborn (UM-D). The requested system will form a fundamental infrastructure to support ongoing multidisciplinary manufacturing-related research activities, including accurate measurement of crack initiation and propagation, quality inspection or damage assessment of engineering structures, failure mechanisms related to crack growth, continuum damage mechanisms related to micro and mesoscale damage evolution, fatigue damage, and formability of engineering materials used in the automotive industry. The main objectives of these studies are to develop a nondestructive methodology capable of accurately determining the micro-structural damage evolution and/or failure mechanisms of engineering materials, to provide a critical linkage between micro/meso and macroscale damage mechanisms, and to develop innovative algorithms for damage assessment of engineering structures through the proposed measurement system. The outcome of the ongoing research activities will lead to: 1) a potential breakthrough in understanding the damage evolution through failure process of engineering materials by measuring and analyzing spatial micro/mesoscale crack growth in complete and continuous loading processes without the need to unload and dissect material specimens; 2) possible coalesce of micro/mesoscale crack growth patterns and damage mechanics; and 3) an accurate way for the damage assessment and residual life prediction of engineering structures under service conditions through spatial fracture crack signatures. The proposed nondestructive measurement system will substantially strengthen the research infrastructure at UM-D and will also significantly improve the education quality at UM-D through undergraduate student design projects and research training. The community outreaching will inspire high-school students' interest in science and engineering, and broaden the participation of underrepresented black minority and female students in Dearborn and Detroit communities.