Microscopic visualization of a granitic rock subject to dynamic tensile loading by using a micro X-ray CT system

The dynamic tension test based on Hopkinson's effect together with the spalling phenomena generates numerous cracks in the test specimens, which are due to the dynamic fracture process and rock inhomogeneity. In the dynamic tensile test, the free surface displacement velocity at the free end is measured with a laser vibration meter and the fractured planes are observed using a high-speed camera. The position where the specimen first fractures is selected as the fracture plane. The position of the fracture plane and measured displacement velocities are then used to determine the dynamic tensile strength. Therefore, it is important to verify the mechanism of the fracture plane formation. In this study, micro X-ray CT system is used to visualize the 3-D microstructure of a rock specimen subject to dynamic tensile loading in a nondestructive manner.