Three-Dimensional Crack Initiation and Propagation in Transparent Rock-Like Material Subject to Compression

9622136这项工作是康奈尔大学和俄克拉何马大学的研究人员合作的，重点是加深对岩石压缩破裂机制的理解。这项研究包括公式和测试，以及独特的实验和计算机模拟，这是确定脆性和岩石材料中任意形状三维裂纹稳定扩展的演化规律所必需的。激光将被用来在透明试件上诱导三维裂纹。这些试件将在压缩载荷下进行测试，以诱导稳定增长和裂纹相互作用。使用透明材料，可以很容易地观察到结构的不稳定性。根据试验结果，将制定三维裂纹扩展准则。现有的计算机模拟器将被应用和扩展，以实现完全三维的裂纹扩展和相互作用。裂纹扩展的演化规则将被编程到该模拟器中，它允许单个内部裂纹、与自由表面相互作用的裂纹以及彼此之间的任意轨迹。在这一目标中要检验的假设是，使用计算机模拟，可接受的规则是这样一种规则，它不仅能够再现实验观察，而且能够在进行额外的验证测试之前预测不断演变的裂纹形状。***

9622136 This work, a collaboration between researchers at Cornell University and the University of Oklahoma, is focused on developing understanding about the mechanisms of rock fracture in compression. The research involves formulation and testing, with unique experiments and computer simulation, necessary to identify the evolution rules for the stable growth of three-dimensional cracks of arbitrary shape in brittle and rock materials. A laser will be used to induce three-dimensional cracks in transparent specimens. These specimens will be tested under compressive loading to induce stable growth and crack interactions. With transparent material, structural instabilities can be easily observed. Based on the test results, three-dimensional crack propagation criteria will be formulated. An existing computer simulator will be applied and extended for fully three-dimensional crack growth and interaction. Evolution rules for crack growth will be programmed into this simulator, which allows arbitrary trajectories of single internal cracks, cracks interacting with free surfaces, and with each other. The hypothesis to be tested within this objective is that, using computer simulation, an acceptable rule is one that will be able not only to reproduce experimental observations, but also will be able to predict evolving crack shapes in additional proof tests before performing them. ***