Numerical study of dimensions effects on measurement of rock fracture characterizations by using the modified Arcan test specimen

Fracture mechanics can be applied to many engineering fields including civil and mining engineering, where drilling, excavation, fragmentation and cutting of rocks are closely related to the strength, stability and :fracture of rock materials and structures. This study presents an application of fracture mechanics to determine the effect of dimensions on mixed-mode fracture properties of rocks by using the numerical analyses. Using the finite-element results, correction factors were applied to the specimens and a polynomial fit was proposed to evaluate the stress intensity factors of a modified version of Arcan specimen with a crack subjected to mixed mode loading. The finite element analyses of bonded joints were also studied for different thickness and crack length. The mixed-mode fracture toughness tests were carried out by using rectangular specimens over a wide range of loading angles. Using the finite element results, non-dimensional stress intensity factors applied to the rectangular fracture specimen. It is also shown that when the ratio of crack length to specimen thickness (a/w) is increased, the stress intensity factors in mode-I and II are raising too. But this growth is tangible in mode-I. On the other hand the proportion of loading in mode-I and II between 60 and 70 degree is same.