CONSIDERATION IN THE FRACTURE OF AN INHOMOGENEOUS MATERIALS WITH PRE-EXISTING CRACKS AND MATERIAL FAULTS.

本文的研究为非均质材料断裂裂纹的扩展特性提供了重要的理论依据。在非均匀材料模型中，主裂纹尖端附近存在相互作用的裂纹和空洞，夹杂物的界面裂纹被视为主裂纹。对断裂裂纹的扩展行为进行了数值模拟和实验研究。主要研究结果如下：1.各向异性轴的方向决定断裂裂纹易扩展或难扩展的现象，表现为各向异性弹性介质中裂纹扩展的性质.由于裂纹与裂纹或裂纹与空洞的位置关系，对裂纹扩展既有中断作用，又有辅助作用.当相互作用的裂纹和孔洞相对于主裂纹不对称存在时，裂纹必然发生扭结现象.界面裂纹扩展行为复杂，能量释放率分布具有不连续性. E积分比J积分更有效地处理了非齐次模型，并得到了许多有效的结果。这些结果为非均匀材料的断裂研究提供了重要的数据。

The important knowlege in relation to the properties for an extension behavior of fracture cracks in an inhomogeneous materials is found out in this research. The inhomogeneous material models have some interacting cracks and voids near the main crack tip and further the interface cracks of an inclusion are treated as the main crack. The extension behavior of a fracture crack is investigated numerically and experimentally. The main results are enumerated followings.1. The phenomenom that it is easy or difficult for a fracture crack to grow on account of the direction of the anisotropic axis, is shown as the property of a crack extension in the anisotropic elastic bady.2. Both of the interruption effect and assistant effect for the crack extension exist because of the positioning relation between crack and crack or crack and void.3. In the case that the interacting crack and void exist asymmetrically with respect to the main crack, crack kinkng phenomenom take place certainly.4. The crack extension behavior of the interface crack is complicated and the distribution of energy release rate has the discontinuity.5. E-integral is more effective than J-integral for the inhomogeneous model treating in this research.Other many valid results are obtain. These results become important datum for the fracture of the inhomogeneous materials.