CMG: Rheology of Damaged Materials with Applications to Deformation in the Earth's Crust

CMG：受损材料的流变学及其在地壳变形中的应用

• 批准号: 0327799
• 负责人: Louise Kellogg
• 金额: $ 48.11万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0327799&HistoricalAwards=false
• 关键词: CMG; Rheology; Damaged; Materials; Applications; CMG; Rheology; Damaged; Materials; Applications

The investigators are exploring new methods for representing damage mechanics in the Earth's crust using a continuum rheology. Using a method that has been developed for understanding phase transitions in liquid crystals, they are developing a new model of damage in a continuum material undergoing shear flow. They model crustal deformation using a fluid phase with anisotropic properties, in which some elastic energy is stored according to the direction of an alignment vector. The undamaged state is characterized by random alignment of the directional vectors (director). Defects can be introduced in various configurations with appropriate alignment of the directors. In response to shear, point defects can develop and merge to trigger spikes in the velocity, that is, slip events. This slip mechanism, followed by subsequent healing, provides a model for the formation of microcracks and stick-slip behavior on faults.Intellectual Merit: Deformation of the Earth's crust and upper mantle has implications for the origins of earthquakes and the mechanisms for plate tectonics. This study of the behavior of this system will address the origins of damage, formation of faults, fault slip, and healing, in the Earth's crust.Broader Impacts: By developing new models of damage rheology, this project will address the underlying mechanisms leading to earthquakes, a scientific problem of fundamental societal importance. A theory of damage in a continuum has potential implications well beyond geophysics, and could be applicable to damage in other continuum materials. In addition, this project establishes a new collaboration between geophysics and applied mathematics, leading to the development of new methods in both fields, while educating a graduate student and a postdoctoral scholar.

研究人员正在探索使用连续性流变学中代表地壳中损害力学的新方法。使用已开发的方法来理解液晶中的相变，它们正在在经历剪切流量的连续体材料中开发新的损伤模型。它们使用具有各向异性特性的流体相对地壳变形进行建模，其中根据比对载体的方向存储一些弹性能。未损坏的状态的特征是定向向量的随机比对（主管）。可以在各种配置中引入缺陷，并适当地对齐董事。为了响应剪切，点缺陷可以发展并合并以触发速度中的尖峰，即滑移事件。这种滑动机制随后进行了愈合，为在断层上形成微裂纹和踩踏行为提供了模型。智能优点：地球和上层地幔的变形对地震的起源以及板块构造的机制具有影响。对该系统行为的这项研究将解决地球上的损害，故障，断层滑移和康复的起源。BROADER的影响：通过开发损害流变学的新模型，该项目将解决导致地震的潜在机制，这是一个基本社会重要性的科学问题。连续体中的损害理论具有远远超出地球物理的潜在影响，并且可能适用于其他连续材料中的损害。 此外，该项目还建立了地球物理和应用数学之间的新合作，从而在两个领域开发了新方法，同时教育研究生和博士后学者。