Abstract: By using CCCD-SHPB (central cracked circular disksplit Hopkinson pressure bar) test system  the pure type Ι loading tests of granite samples under different loading rate were carried out, the relationship between the average loading curvesP(t)and time was measured. The things gained above are used in the promoted central cracked circle disk specimen stress intensity factors calculation formula to obtain the dynamic fracture toughness of the granite under different loading rates and reveal the relationship between loading rate and dynamic fracture toughness. The results show that in the loading rate range from 50 to 350 GPa·m1/2/s, the fracture toughness has a linear upward trend with the increase of loading rate.  

Key words: dynamic fracture toughness； loading rate； split Hopkinson pressure bar (SHPB)； , central cracked circular disk (CCCD)