Mechanical and energy dissipation characteristics of granite under different impact loads

Abstract:

To explore the dynamic characteristics of granite under different impact loading conditions, single and repeated impact tests of granite samples were carried out by the split Hopkinson pressure bar respectively. The stress-strain response, strain rate curve, energy dissipation characteristics, and the failure modes of the samples were analyzed. Results show that in the single impact test, the relationship between the dynamic compressive strength and the specific energy presented a logarithmic function. The damage degree of the granite sample aggravated gradually with the increase of the specific energy. With the increase of the incident peak stress, the curve of the strain rate showed a "double-peak" form, and the second peak gradually became larger than the first peak. The rebound phenomenon of the stress-strain curve in the post-peak phase tapered off. In the repeated impact test, when the sample did not fail, the stress-strain curve generally experienced three stages, i.e., elastic loading, damage evolution, and post-peak rebound. When the sample underwent the last impact, the post-peak shape of the stress-strain curve was related to the failure degree of the sample. In addition, it was found that as the accumulative specific energy increased, the damage degree of the granite samples increased, and the curve of the strain rate gradually transited from "single-peak" to "double-peak".