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

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流变学来表示地壳损伤力学的新方法。他们正在利用一种为理解液晶相变而开发的方法，开发一种新的剪切流连续材料损伤模型。他们使用具有各向异性特性的流体相来模拟地壳变形，其中根据对齐矢量的方向存储一些弹性能量。未损坏状态的特征是方向矢量（导向器）的随机对齐。通过适当调整董事，可以在各种配置中引入缺陷。为了响应剪切，点缺陷会发展并合并以触发速度峰值，即滑移事件。这种滑动机制，以及随后的愈合，为断层上微裂纹的形成和粘滑行为提供了一个模型。智力价值：地壳和上地幔的变形对地震的起源和板块构造机制具有影响。这项对该系统行为的研究将解决地壳中损伤的起源、断层形成、断层滑移和愈合问题。更广泛的影响：通过开发损伤流变学的新模型，该项目将解决导致损伤流变学的潜在机制。地震，一个具有根本性社会重要性的科学问题。连续体损伤理论的潜在影响远远超出了地球物理学的范围，并且可以适用于其他连续体材料的损伤。 此外，该项目在地球物理学和应用数学之间建立了新的合作，导致这两个领域新方法的发展，同时培养研究生和博士后学者。