Isostaticity at Frictional Jamming

作     者：Stefanos Papanikolaou Corey S. O’Hern Mark D. Shattuck 

作者机构：Departments of Mechanical Engineering & Materials Science Yale University New Haven Connecticut 06520 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Benjamin Levich Institute and Physics Department The City College of the City University of New York New York New York 10031 USA 

出 版 物：《Physical Review Letters》 (Phys Rev Lett)

年 卷 期：2013年第110卷第19期

页      面：198002-198002页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：National Science Foundation  NSF  (0821132  0968013) 

主　　题：DEGREES of freedom COMPUTER simulation STATIC friction PACKING fractions DENSITY of states 

摘      要：Amorphous packings of frictionless, spherical particles are isostatic at jamming onset, with the number of constraints (contacts) equal to the number of degrees of freedom. Their structural and mechanical properties are controlled by the interparticle contact network. In contrast, amorphous packings of frictional particles are typically hyperstatic at jamming onset. We perform extensive numerical simulations in two dimensions of the geometrical asperity (GA) model for static friction to further investigate the role of isostaticity. In the GA model, interparticle forces are obtained by summing up purely repulsive central forces between periodically spaced circular asperities on contacting grains. We compare the packing fraction, contact number, mobilization distribution, and vibrational density of states (in the harmonic approximation) using the GA model to those generated using the Cundall-Strack approach. We find that static packings of frictional disks obtained from the GA model are mechanically stable and isostatic when we consider interactions between asperities on contacting particles. The crossover in the structural and mechanical properties of static packings from frictionless to frictional behavior as a function of the static friction coefficient coincides with a change in the type of interparticle contacts and the disappearance of a peak in the density of vibrational modes for the GA model. These results emphasize that mesoscale features of the model for static friction play an important role in determining the properties of granular packings.