Rock fracture characterization using the modified Arcan test specimen

This study presents an application of fracture mechanics to determine mixed-mode fracture properties of rock using the numerical and experimental methods. The modified version of Arcan specimen test was, in association with a special loading device, an appropriate apparatus for experimental mixed-mode fracture analysis. 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 specimens were also studied for various materials, different thickness and crack length. The mixed-mod fracture-toughness tests were carried out by using the modified Arcan test specimens over a wide range of loading angles. Using the finite element results, non-dimensional stress-intensity factors applied to the fracture specimen. By employing experimentally measured critical loads and the aid of the finite element method, mixed-mode fracture toughness for rock under consideration determined. The fracture surfaces under different mixed-mode loading conditions were examined by optical and scanning electron microscopy (SEM) to gain insight into the failure surfaces.