72 research outputs found
Binomial multiplicative model of critical fragmentation
We report the binomial multiplicative model for low impact energy
fragmentation. Impact fragmentation experiments were performed for low impact
energy region, and it was found that the weighted mean mass is scaled by the
pseudo control parameter multiplicity. We revealed that the power of this
scaling is a non-integer (fractal) value and has a multi-scaling property. This
multi-scaling can be interpreted by a binomial multiplicative (simple biased
cascade) model. Although the model cannot explain the power-law of
fragment-mass cumulative distribution in fully fragmented states, it can
produce the multi-scaling exponents that agree with experimental results well.Comment: 10 pages, 6 figures, A typo in Eq.(6b) was improved in Ver.
Explosive fragmentation of thin ceramic tube using pulsed power
This study experimentally examined the explosive fragmentation of thin
ceramic tubes using pulsed power. A thin ceramic tube was threaded on a thin
copper wire, and high voltage was applied to the wire using a pulsed power
generator. This melted the wire and the resulting vapor put pressure on the
ceramic tube, causing it to fragment. We examined the statistical properties of
the fragment mass distribution. The cumulative fragment mass distribution
obeyed the double exponential or power-law with exponential decay. Both
distributions agreed well with the experimental data. We also found that the
weighted mean fragment mass was scaled by the multiplicity. This result was
similar to impact fragmentation, except for the crossover point. Finally, we
obtained universal scaling for fragmentation, which is applicable to both
impact and explosive fragmentation.Comment: 5 pages, 6 figure
Force Chain Evolution in a Two-Dimensional Granular Packing Compacted by Vertical Tappings
We experimentally study the statistics of force-chain evolution in a
vertically-tapped two-dimensional granular packing by using photoelastic disks.
In this experiment, the tapped granular packing is gradually compacted. During
the compaction, the isotropy of grain configurations is quantified by measuring
the deviator anisotropy derived from fabric tensor, and then the evolution of
force-chain structure is quantified by measuring the interparticle forces and
force-chain orientational order parameter. As packing fraction increases, the
interparticle force increases and finally saturates to an asymptotic value.
Moreover, the grain configurations and force-chain structures become
isotropically random as the tapping-induced compaction proceeds. In contrast,
the total length of force chains remains unchanged. From the correlations of
those parameters, we find two relations: (i) a positive correlation between the
isotropy of grain configurations and the disordering of force-chain
orientations, and (ii) a negative correlation between the increasing of
interparticle forces and the disordering of force-chain orientations. These
relations are universally held regardless of the mode of particle motions
with/without convection
Crossover of the weighted mean fragment mass scaling in 2D brittle fragmentation
We performed vertical and horizontal sandwich 2D brittle fragmentation
experiments. The weighted mean fragment mass was scaled using the multiplicity
. The scaling exponent crossed over at . In the
small regime, the binomial multiplicative (BM) model was
suitable and the fragment mass distribution obeyed log-normal form. However, in
the large regime, in which a clear power-law cumulative
fragment mass distribution was observed, it was impossible to describe the
scaling exponent using the BM model. We also found that the scaling exponent of
the cumulative fragment mass distribution depended on the manner of impact
(loading conditions): it was 0.5 in the vertical sandwich experiment, and
approximately 1.0 in the horizontal sandwich experiment.Comment: 5 pages, 3 figure
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