The role of tap duration for the steady-state density of vibrated granular mediaJ. A. Dijksman and M. van Hecke
Kamerlingh Onnes Lab, Universiteit Leiden - Postbus 9504, 2300 RA Leiden, The Netherlands
received 28 July 2009; accepted in final form 30 October 2009; published November 2009
published online 2 December 2009
We revisit the problem of compaction of a column of granular matter exposed to discrete taps. We accurately control the vertical motion of the column, which allows us to vary the duration T and the amplitude A of single-cycle sinusoidal taps independently. We find that the density of the material at the reversible branch depends both on A and T. By comparing the densities on the reversible branches obtained for a range of values of T, we find that we can collapse all data when plotted as a function of A/T, which scales similar to both the liftoff velocity and the time of flight of the packing. We further show that switching between states obtained for different A and T, but chosen such that their densities on the reversible branches match, does not lead to appreciable hysteresis. We conclude that the appropriate control parameter for sinusoidal tapping is not the peak acceleration ~ A/T2, as is usually assumed, but rather ~ A/T.
45.70.-n - Granular systems.
45.70.Cc - Static sandpiles; granular compaction.
81.20.Ev - Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation.
© EPLA 2009