Effect of strain rate on macro- and micro-failure characteristics of marble from SHPB tests

Abstract

A rock's microstructural characteristics reflect its macroscopic mechanical properties. Here, the effect of impact load on the microstructural characteristics of fractured rock is investigated, based on the split Hopkinson pressure bar compression test results for marble, and using a scanning electron microscope (SEM) to analyse fracture morphology. SEM results show that rock fractures under impact load are typical brittle failures. The fracture morphology reveals mainly a transgranular fracture mode, also containing intergranular fracture characteristics. Fractural microstructure exhibits strain rate effect, and with increased impact load, the fracture surface details become rougher and the quantity of scattered crystal particles increases, while the transgranular features become more apparent, the results of which are consistent with the macroscopic mechanical test results on rock.