Propagation of explosive pulses in assemblies of disks and spheres

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An experimental investigation has been conducted to compare and contrast the dynamic load-transfer process in single-chain assemblies of two- and three-dimensional particles. In particular, single-chain assemblies of disks and spheres were subjected to explosive loadings and strain gauges were used to collect the resulting strain pulse information. The data were analyzed to compare the pulse velocity, contact load attenuation, dispersion, and pulse breakup in disks and spheres. The comparison shows that the average pulse velocity in disks is higher than in spheres and the pulse attenuation is lower in the disks. The results also show that there is a characteristic pulse that will propagate through a single chain of disks without significant dispersion. However, the characteristic pulse propagating in assemblies of spheres shows dispersion. For both disks and spheres, when the input pulse is sufficiently long, it undergoes a ringing process, which breaks the long pulse up into smaller signals of size approximately equal to the characteristic length. The larger the input pulse is with respect to the characteristic pulse length, the longer the breakup takes. This breakup is also accompanied by a redistribution of energy, which is easily seen in the frequency domain.

Publication Title

Journal of Engineering Mechanics