CiteULike: dchen's deformation

Emulsion drops in external flow fields -- The role of liquid interfaces

Peter Fischer — 2008-07-24T20:48:20-00:00

Current Opinion in Colloid & Interface Science, Vol. 12, No. 4-5. (October 2007), pp. 196-205.

We review the flow of emulsion drops, focusing on recent work involving complex interfaces, which may include the presence of surfactants, particles, surface-active polymers, or solid-like membrane layers. En route, important phenomena in multiphase flow associated with emulsion rheology are considered, including drop coalescence and breakup, surfactant transport, or the mechanics of composite interfaces.

Observation of Droplet Size Oscillations in a Two-Phase Fluid under Shear Flow

Laurent Courbin — 2008-07-19T21:16:25-00:00

Physical Review Letters, Vol. 92, No. 1. (January 2004), 018305.

Monte Carlo study of crystalline order and defects on weakly curved surfaces

A Hexemer — 2008-06-10T16:29:38-00:00

Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 76, No. 5. (2007)

We numerically study the ground states of particles interacting via a repulsive Yukawa potential on two rigid substrates shaped as isolated and periodically arranged bumps characterized by a spatially varying Gaussian curvature. Below a critical aspect ratio that describes the substrate deformation, the lattice is frustrated, but defect free. A further increase of the aspect ratio triggers defect unbinding transitions that lower the total potential energy by introducing dislocations either in isolation or within grain boundaries. In the presence of very strong deformations, isolated disclinations are nucleated. We show that the character and spatial distribution of defects observed in the ground state reflect the symmetries and periodicity of the two model surfaces investigated in this study.

Microscopic origin of granular ratcheting

S Mcnamara — 2008-06-09T19:58:04-00:00

Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 77, No. 3. (2008)

Numerical simulations of assemblies of grains under cyclic loading exhibit “granular ratcheting:” a small net deformation occurs with each cycle, leading to a linear accumulation of deformation with cycle number. We show that this is due to a curious property of the most frequently used models of the particle-particle interaction: namely, that the potential energy stored in contacts is path dependent. There exist closed paths that change the stored energy, even if the particles remain in contact and do not slide. An alternative method for calculating the tangential force removes granular ratcheting.

PLASTIC-DEFORMATION AND FAILURE IN GRANULAR MEDIA.pdf

2008-04-28T18:44:15-00:00

Force, relative-displacement, and work networks in granular materials subjected to quasistatic deformation

NP Kruyt — 2008-04-26T22:31:19-00:00

Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 5. (2007)

To describe the heterogeneous nature of stress transmission in granular materials, the concept of the “strong” network consisting of contacts with large normal forces has been proposed by Radjaï et al. [Phys. Rev. Lett. 80, 61 (1998)]. The shear stress is mainly determined by this strong network. The dual viewpoint is adopted here, by not only considering the forces at contacts, but also the deformation. It is shown that the strain increments are determined by the tangential component of the relative displacements at the contacts. A “mobile” network consisting of contacts with large tangential relative displacements is defined that primarily accounts for the strain increments. The investigation of the relation between the strong and the mobile networks shows that these networks are largely unrelated. An alternative network is defined that consists of contacts at which the contribution to the work input is large. It is found that this work input occurs primarily through the tangential forces and tangential relative displacements.