Dynamic effective mass of granular media.
We develop the concept of frequency dependent effective mass, M[over ](omega), of jammed granular materials which occupy a rigid cavity to a filling fraction of 48%, the remaining volume being air of normal room condition or controlled humidity. The dominant features of M[over ](omega) provide signatures of the dissipation of acoustic modes, elasticity, and aging effects in the granular medium. We perform humidity controlled experiments and interpret the data in terms of a continuum model and a "trap" model of thermally activated capillary bridges at the contact points. The results suggest that attenuation of acoustic waves in granular materials can be influenced significantly by the kinetics of capillary condensation between the asperities at the contacts.
Hsu
Chaur-Jian
CJ
Schlumberger-Doll Research, One Hampshire Street, Cambridge, Massachusetts 02139, USA.
Johnson
David L
DL
Ingale
Rohit A
RA
Valenza
John J
JJ
Gland
Nicolas
N
Makse
Hernán A
HA