Investigation of the rate dependence of fracture propagation in rocks using digital image correlation (DIC) method

Loading rate is the main controlling factor in dynamic failure of rocks. In this paper, digital image correlation (DIC) combined with ultra-high speed photography is utilized to study the loading rate effect of a granitic rock - Laurentian granite using notched semi-circular bend (NSCB) method. The dynamic stress intensity factors and crack tip positions are determined from the displacement fields obtained using DIC. Fracture time, fracture toughness and crack growth velocity all exhibit loading rate dependence. The dependence of fracture propagation toughness on crack growth velocity is also obtained, which is in good agreement with that reported in the literature. (C) 2015 Elsevier Ltd. All rights reserved.