PROPAGATION OF EXPLOSIVE PULSES IN ASSEMBLIES OF DISKS AND SPHERES

An experimental investigation has been conducted to compare and contra st the dynamic load-transfer process in single-chain assemblies of two -and three-dimensional particles. In particular, single-chain assembli es of disks and spheres were subjected to explosive loadings and strai n gauges were used to collect the resulting strain pulse information. The data were analyzed to compare the pulse velocity, contact load att enuation, dispersion, and pulse breakup in disks and spheres. The comp arison shows that the average pulse velocity in disks is higher than i n spheres and the pulse attenuation is lower in the disks. The results also show that there is a characteristic pulse that will propagate th rough a single chain of disks without significant dispersion. However, the characteristic pulse propagating in assemblies of spheres shows d ispersion. For both disks and spheres, when the input pulse is suffici ently long, it undergoes a ringing process, which breaks the long puls e up into smaller signals of size approximately equal to the character istic length. The larger the input pulse is with respect to the charac teristic pulse length, the longer the breakup takes. This breakup is a lso accompanied by a redistribution of energy, which is easily seen in the frequency domain.