Application of DIC Technique for Studies of Kuru Granite Rock under Static and Dynamic Loading

Effects of strain rate and confining pressure on the compressive behavior of Kuru granite

“…This leads to simultaneous initiation and propagation of multiple cracks and finally complete pulverization of the sample, as well as a fast release of elastic strain energy as kinetic energy of the rock particles, acoustic emission, and generation of frictional heat. Another consequence of this is that the scatter observed in the low strain rate testing of brittle materials is typically smaller at high strain rates [7,9], since the deformation or fracture is not anymore localized only at the weakest area of the sample. In this paper, however, the scatter in the low rate tests is somewhat lower than in the high strain rate tests, which may be explained by the size effect.…”

“…The effect of strain rate on the mechanical behavior of various rocks has been widely studied in compression [3,4], tension [5][6][7][8][9], and bending [1,10]. Liang et al [11] studied the effects of loading rate on the fracture characteristics in the quasi-static region of granite rock.…”

Experimental and numerical study of drill bit drop tests on Kuru granite

“…The specimens were loaded under quasi-static and dynamic loading conditions to give information about the strainrate sensitivity of the tensile and compressive strengths. For a complete description of the experimental procedure and results, the reader is referred to [16] for quasi-static confined compression and Brazilian disc tests, [17] for dynamic confined compression tests with SHPB, and [10] for dynamic Brazilian disc tests with SHPB. Figure 1 summarizes these experimental data in terms of differential stress versus pressure at peak stress.…”

“…Hence, the strain-rate sensitivity and eventual coupling with pressure sensitivity are also of special interest. The behaviour of granite rock under dynamic loading conditions has been investigated using dedicated experimental apparatus such as split Hopkinson pressure bars (SHPB) [10,11]. The combined effect of strain rate and confining pressure was originally investigated by mean of rigs added to SHPB specimens, but did not provide a constant confinement during the tests.…”

Experimental investigation of the mechanical properties of Alfas stone

“…The issue of the different strain values measured on the opposite sides of the disc specimens is intriguing and a number of experimental options are currently being studied / explored by the authors in order to investigation this discrepancy. One way to reduce experimental errors due to utilization of strain gages is to use optical techniques such as the procedure of Digital Image Correlation (DIC) [23,24] which does not depend on the accurate placement of measuring devices on each specimen. In order to investigate this issue, both sides of a specimen need to be monitored at the same time.…”