PNNL

Abstract

Dynamic compression/shear experiments on a borosilicate glass at the average strain rate of 250s-1 are conducted using a modified version of Split Hopkinson Pressure Bar (SHPB). Instead of applying confining pressure, cuboid specimens with the material axis inclining to the loading direction at different angles (0°, 3°, 5° and 7°) are used to generate higher shear stresses. A high-speed digital camera, synchronized with the loading stress pulse, is used to record the dynamic crack initiation and propagation. Experimental results show that the equivalent stress at failure decreases with increasing shear portion in the stress. Digital images show that the cracks initiate randomly in the right specimen, whereas cracks initiate from the stress concentrated corners in the inclined specimens. Subsequent crack propagation, despite of specimen inclination angles, is along the specimen axis rather than the compressive loading direction.