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Title: Investigation of Fracture Process Zone in Barre Granite under Mode II Loading
Fracturing in brittle rocks exhibits a significant nonlinear region surrounding the crack tip called the fracture process zone (FPZ). In this study, the evolution of the FPZ under pure mode II loading using notched deep beam under three-point loading was investigated. The experimental setup included the simultaneous monitoring of surface deformation using the two-dimensional digital image correlation technique to characterize various crack characteristics such as its type and FPZ evolution in Barre granite specimens. Both displacement and strain approaches of the two-dimensional digital image correlation were used to identify the mode of fracture under pure mode II loading. Both approaches showed that the crack initiation occur under mode I despite the pure mode II loading at the notch tip. The displacement approach was used for characterizing the evolution of the FPZ which analyzed the crack tip opening displacement and crack tip sliding displacement to identify the transition between the three stages of FPZ evolution, namely, (a) elastic stage, (b) formation of the FPZ, and (c) the macro-crack initiation. The results showed that the evolution of the FPZ of mode I fracture under pure mode II loading is similar to cases of pure mode I loading of the same rock.  more » « less
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55th US Rock Mechanics/Geomechanics Symposium
Medium: X
Sponsoring Org:
National Science Foundation
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