Characteristic Length of Quasi-Brittle Materials

准脆性材料的特征长度

• 批准号: 0070062
• 负责人: Joseph Labuz
• 金额: $ 20.8万
• 依托单位: University of Minnesota-Twin Cities
• 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: 2000-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0070062&HistoricalAwards=false
• 关键词: Characteristic; Length; Quasi; Brittle; Materials

CMS-0070062"Characteristic Length of Quasi-Brittle Materials"PI: Joseph LabuzUniversity of Minnesota-Twin CitiesAbstract:Field and laboratory observations of rock failure indicate behavior quite different for structures of various size and shape. Due to the existence of a localized zone of microcracking, which seems to be a characteristic of the material, the nominal strength and the global response of a given geometry and load configuration of a rock structure are dependent on size. For many problems in geotechnical engineering (for instance, breakouts in tunneling, comminution and drilling, pullout of reinforcement), the characteristics of a localized zone are important in predicting failure. The objective of this research is to measure the characteristic length of various rocks. The localized zone of microcracking prior to failure will be mapped with locations of acoustic emission, and space-time clustering analyses will help to define the dimensions. As a complementary method, electronic speckle pattern interferometry will be used to measure surface deformation, providing a high resolution visual image of the displacement field. Numerical modeling with a distinct element code will provide a basis for the extension of the experimental results to other materials and conditions. By performing simulations designed to mimic the experimental measurements, the necessary constitutive behavior can be established, and the investigation of boundary value problems can be realized.

CMS-0070062“准脆性材料的特征长度”PI：Joseph LabuzUniversity of Minnesota-Twin Cities摘要：岩石破坏的现场和实验室观察表明，不同尺寸和形状的结构的行为完全不同。 由于存在微裂纹的局部区域，这似乎是材料的特性，岩石结构的给定几何形状和载荷配置的标称强度和整体响应取决于尺寸。 对于岩土工程中的许多问题（例如，隧道开挖、粉碎和钻孔、钢筋拔出），局部区域的特征对于预测破坏非常重要。 本研究的目的是测量各种岩石的特征长度。 在破坏前的微裂纹的局部区域将被映射与声发射的位置，和时空聚类分析将有助于定义的尺寸。 作为一种补充方法，电子散斑干涉法将被用来测量表面变形，提供一个高分辨率的位移场的视觉图像。 数值模拟与一个独特的元素代码将提供一个基础的实验结果扩展到其他材料和条件。 通过模拟实验测量，可以建立必要的本构行为，并可以实现边值问题的研究。