Stress Intensity Factors of Tearing Fracture (Mode III) on Anisotropic Rocks Using Boundary Element Method

• Main Authors: Jiun-jia Tu, 涂峻嘉
• Other Authors: Chao-hsu Chen
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/48109357808932180700

碩士 === 國立成功大學 === 資源工程學系碩博士班 === 97 === Numerical technique in rock fracture mechanics have become indispensable tools for solving all kinds of science and engineering problems. Extensive research has been carried out for the development of new numerical methods to determine the stress intensity factors (SIFs). Due to the varied engineering conditions in the practical area, it is imperative to develop new numerical methods or to explore alternative techniques for the purpose of solving the complicated problems and to improve the efficiency and accuracy of the existing or new numerical methods. In recent years, scholars investigate methods of the various tests and focus on the mode-I, mode-II and mixed-mode I-II. The mode III fracture is still in the initial stage. However, the rock mass often occur in mode-III fracture under load in underground engineering and slope engineering. Thus, the development of mode-III SIF will help to study the behavior of rock fracture. This thesis presents the dual boundary element methods (dual-BEM) or single-domain BEM to analyze anisotropic rocks in mode-III fracture and adopts the Fortran language to develop the numerical program. For anisotropic rocks of mode-III fracture, the SIF along the crack front can be discussed. The aim of these discussions are to compare the variation of SIFs (KI, KII and KIII) for different crack length, material width, material inclined angle and the anisotropic influence in transversely isotropic material. Further, the value of KIII can be discussed. The results show that the SIFs (KII, KIII) is a parabolic distribution when the loading directs the vertical and parallel crack fronts crack in the rocks within a center crack. For the edge crack, the higher values of SIFs (KII, KIII) occur at the deeper crack or smaller ratios of length and width. The results also proved that the SIF is an ability to resist and the greater SIF occur at the easier arrives failure. This study provides three-dimensional test method, and its characteristics is that control mode-I and mode-II fractures (i.e. KI, KII near to zero), then approximate the pure mode-III fracture test. Finally, this study can provide the reference for the mode-III test.