Abstract:In order to investigate the effects of stress waveforms on energy dissipation and the degree of fragmentation of rock. SHPB experiments on rock using rams with different structures and geometries have been performed. The efficiency of energy absorption and post-fragmentation grain sizes under diffferent loading conditions have been determined. The results show that both energy absorption and the degree of fragmentation of rock are related to the shapes of incident stress waves. From the view of energy economization. the approximately symmetric bell-shaped pulse produced by a truncated cone ram is apparently superior to an exponentiallyattenuation pulse provided that the incident energy is great enough to fragment the rock. But no matter what the intensities and shapes of the loading pulses are. the maximum energy absorption of rock can not be more than 50％ of the incident energy.

Key words: rock fragmentation dynamics stress wave dissipation and economization of energy