CAREER: In-Situ Characterization of Materials

职业：材料的原位表征

• 批准号: 9985264
• 负责人: Ersan Ustundag
• 金额: $ 32.45万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9985264&HistoricalAwards=false
• 关键词: CAREER; Situ; Characterization; Materials

9985264UstundagThis grant presents a detailed CAREER plan that will employ the latest improvements in neutron and X-ray diffraction instruments to characterize the response of individual phases in a composite to applied loading. Model specimens are prepared that are essentially fibrous composites, and progress from a single fiber to an array of fibers and finally to a three-dimensional stacking of fibers approaching the geometry of "real" composites. The specimens are loaded under an X-ray or neutron beam to measure the strain response of each phase. By varying applied stress and temperature, crucial phenomena is determined, such as in-situ yield stress, matrix or fiber cracking, interface debonding, evolution of load sharing due to creep in one phase, interactions between neighboring fibers, and evolution of damage zones. The overall macroscopic response of the composite is measured via strain gauges or extensometers attached to its surface. The main goal is to provide reliable mechanical behavior data that will lead to development of constitutive equations that take into account the in-situ behavior of each phase. The education activities include research experience for undergraduate students at Caltech and in national laboratories; new course development that leads to a more balanced Materials Science curriculum at Caltech; and adaptation of advanced computational tools in teaching, especially the use of the Internet in research and education. %%%Materials with complicated microstructures or multiple phases (composites) are becoming increasingly prevalent, especially in critical applications such as aerospace structures and engine components. The successful application of these complex materials requires knowledge about the in-situ, co-deformation of each phase. This deformation, however, has not been investigated systematically. In order to develop more sophisticated micromechanics models and to eventually improve the design of composites, detailed information on multiscale deformation behavior of each phase comprising a composite is needed.***

9985264Ustundag 这项拨款提出了详细的职业计划，该计划将采用中子和 X 射线衍射仪器的最新改进来表征复合材料中各个相对施加载荷的响应。制备的模型样本本质上是纤维复合材料，并从单根纤维发展到纤维阵列，最后发展到接近“真实”复合材料几何形状的纤维三维堆叠。将样本加载在 X 射线或中子束下，以测量每个相的应变响应。通过改变施加的应力和温度，可以确定关键现象，例如原位屈服应力、基体或纤维开裂、界面脱粘、由于一相蠕变而导致的负载共享的演变、相邻纤维之间的相互作用以及损坏区域的演变。复合材料的整体宏观响应是通过附着在其表面的应变计或引伸计来测量的。主要目标是提供可靠的机械行为数据，从而开发考虑每个相的原位行为的本构方程。教育活动包括为加州理工学院和国家实验室的本科生提供研究经验；新课程的开发使加州理工学院的材料科学课程更加平衡；在教学中采用先进的计算工具，特别是在研究和教育中使用互联网。 %%%具有复杂微观结构或多相（复合材料）的材料变得越来越普遍，特别是在航空航天结构和发动机部件等关键应用中。这些复杂材料的成功应用需要了解每个相的原位共同变形。然而，这种变形尚未得到系统的研究。为了开发更复杂的微观力学模型并最终改进复合材料的设计，需要有关复合材料各相的多尺度变形行为的详细信息。***