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PY Lai

Publications and source records attributed to PY Lai.

14 recordsLinked to original sources
PubMed2001

Jamming of Granular Flow in a Two-Dimensional Hopper.

We study experimentally the jamming phenomenon of granular flow of monodisperse disks of D = 5 mm diameter in a two-dimensional hopper with opening R. The jamming probability J(d) is measured where d identical withR/D. We found that J(d) decreases from 1 to zero when d increases from 2 to 5. From observing the disk configurations of the arch in the jamming events, the jamming probability can be explained quantitatively by treating the arch as the trajectory of a restricted random walker.

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PubMed2000

Symmetric heaping in grains: a phenomenological model

Heap formation of granular materials in a vertical vibrating bed is studied by a simple model using the profile of the heap as the dynamic variable. Vibration increases the local height, but is counterbalanced by the nonlinear coupling, which tends to suppress the growth of the height. The steady state heap can be solved in closed form in terms of Jacobian elliptic functions. Phenomena such as heap formation and downward and upward heaps can be reproduced. Our results agree with the experimentally observed change of downward to upward steady heaps as the vibration strength is increased. Predictions from the model compare favorably with experimental results on heap profiles and heaping angles.

Journal Article↗
PubMed2000

Rigorous solution for the elasticity of diluted gaussian spring networks

We present a rigorous solution of the elasticity of the diluted Gaussian spring networks (DGSNs) at zero temperature. We show that the deformation of a diluted DGSN is homogeneous provided that the displacements of the particles on the boundary are homogeneous. It follows that at zero temperature the nonvanishing elastic stiffness coefficients are proportional to the hydrostatic pressure in both two and three dimensions. Follows a rigorous proof of the equivalence of the elasticity of the DGSN and the conductance of the random resistor network at zero temperature.

Journal Article↗