CAREER: Modeling and Characterization of Microstructure-Induced Toughening in Ceramic Composites with Multiple Micro and Nano Size Scales

9984298本研究关注先进陶瓷中微观结构增韧效应的计算和实验表征。本论文的研究重点是一种具有良好性能的新型TiB_2/Al_2 O_3陶瓷复合材料体系，它将（1）产生一种用于多尺度显式断裂模拟的新的微观力学方法，（2）表征微观结构形态、相长度尺度、组分性质和界面结合对断裂抗力的影响，（3）阐明具有多种尺寸尺度微观结构的陶瓷复合材料的失效模式并开发失效模型，（4）通过微观结构修正识别性能增强的机制。使用时间分辨诊断的损伤启动、损伤进展和故障的时间依赖性过程。实验将被用来允许施加的负载，时间分辨的响应，和微观损伤的直接相关性。该计划的教育部分包括本科课程开发在格鲁吉亚技术，推广到当地高中学生和教师招聘和工程意识，推广到少数民族学生招聘，并推广到当地少数民族机构。课程改革认识到工程力学教育中课堂教学缺乏动手实验的弊端。这项工作的重点是加强格鲁吉亚理工学院的机械工程本科课程，通过课堂学习与实验室实验的适当整合。这项工作的一个新特点是使用在拟议的研究中开发的实验技术，以促进全面的工程分析能力的发展。课程创新和推广将使用也用于研究的设施，提供研究生研究，本科生参与，课程开发和推广的自然协同作用。

9984298This research concerns on the computational and experimental characterization of microstructural toughening effects in advanced ceramics. Focusing on a new TiB2/Al2O3 ceramic composite system with very promising properties, it will (1) yield a novel micromechanical approach for explicit fracture modeling over multiple size scales, (2) characterize the effects of microstructural morphologies, phase length scales, constituent properties, and interphase bonding on fracture resistance, (3) elucidate the failure modes and develop failure models for ceramic composites with microstructures of multiple size scales, and (4) identify mechanisms for property enhancement through microstructural revisions.Combined modeling and experiments will focus on the full, time-dependent process of damage initiation, damage progression and failure using time-resolved diagnostics. Experiments will be used to allow direct correlation of applied loading, time-resolved response, and microscopic damage. The education component of this program consists of undergraduate curriculum development at Georgia Tech, outreach to local high school students and teachers for recruitment and engineering awareness, outreach to minority students for recruitment, and outreach to a local minority institution. The curriculum innovation recognizes the drawback of classroom instruction without hands-on experimentation in engineering mechanics education. This effort focuses on strengthening Georgia Tech's undergraduate curriculum in mechanical engineering through proper integration of classroom learning with laboratory experimentation. A novel feature of this effort is the use of an experimental technique developed in the proposed research to facilitate the development of an aptitude for comprehensive engineering analysis. The curriculum innovation and outreach will use the facilities also used for research, offering a natural synergy of graduate research, undergraduate participation, curriculum development, and outreach.