Abstract
To investigate the dynamic tensile failure process of coal subjected to impact loading, this study used high-speed camera photography and digital image correlation technology to capture the dynamic tensile failure of coal under impact loading. The dynamic tensile evolution from initial stress to failure was quantitatively analyzed. The captured coal fracture images were processed, and the fractal dimension was used to quantitatively describe the surface crack evolution of coal under impact loading. The following conclusions were drawn from the experimental results: (1) An empirical formula was established to describe the dynamic tensile strength characteristics of coal under different loading rates. (2) During the loading process of Brazilian disc coal samples under impact loading, the maximum strain first appeared at the contact end between the sample and the incident rod. (3) Under impact loading, the Brazilian disc coal sample cracked from the center of the sample and the crack subsequently extended toward both ends. The fractal dimension of the crack exhibited a power exponential relationship with time, and the variation range of the fractal dimension of the crack was in the range of 1.05–1.39.