Uniaxial compression tests on granite and its complete stress-strain relationship at high strain rates

The dynamic strength, complete stress-strain and strain rate relationship of the Bukit Timah granite measured on a split Hopkinson pressure bar (SHPB) using a modified loading method have been obtained. The half-sine loading waveform is generated by a shaped projectile and is specially designed for the 75 mm diameter SHPB. The test samples are 70 mm in diameter and they were cored from a granite block obtained from an underground cavern site. The cut surfaces of every sample were ground to a smooth finish and checked to ensure that it is perpendicular to the length. Results of this test series are compared with data obtained from a conventional loading method. The experimental results reinforce the notion that the half-sine wave generated by a shaped projectile is an ideal incident wave in the determination of the dynamic strength and complete stress-strain and strain rate relationship of granite and other brittle engineering materials in a large diameter SHPB.