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

9625406这项工作是康奈尔大学和俄克拉何马大学研究人员的合作，重点是发展对岩石压缩破裂机制的理解。该研究涉及制定和测试，通过独特的实验和计算机模拟，以确定脆性和岩石材料中任意形状的三维裂纹的稳定扩展的演化规律。将使用激光在透明样品中诱导三维裂纹。这些试样将在压缩载荷下进行测试，以诱导稳定的生长和裂纹相互作用。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，制定三维裂纹扩展准则。现有的计算机模拟器将应用和扩展为全三维裂纹扩展和相互作用。裂纹扩展的演化规则将被编程到这个模拟器中，它允许单个内部裂纹的任意轨迹，裂纹与自由表面的相互作用以及彼此之间的相互作用。在本目标中要测试的假设是，使用计算机模拟，一个可接受的规则不仅能够再现实验观察结果，而且能够在执行其他证明测试之前预测裂纹形状的演变。＊＊＊

9625406 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. ***