Name:COMPACTION
Description:Simulation of the compaction of granular materials
Abstract:The microscopic understanding of the macroscopic material behavior of granular materials such as sand or powder is one of today’s great challenges in material science and physics. Granular media are discontinuous, inhomogeneous, disordered, and anisotropic on a ”microscopic” scale, and their behavior is usually nonlinear and history dependent. Settling of a vibrated granular material into a more compact state is important to a wide range of industries and in many technological processes in which the density of granular solids needs to be controlled. We develop a two-dimensional computer simulation approach to relaxation in a vibrated powder where we focus, by analyzing cooperative dynamics in the powder, on the effects of vibration on the compactivity and the structure of a granular pile.<BR/>Classical molecular dynamics (MD) is a commonly used computational tool for simulating the properties of liquids, solids, and granular materials. Each of the N particles in the simulation is a treated as a point mass and Newton’s equations are integrated to compute their motion. From the motion of the ensemble of particles a variety of useful microscopic and macroscopic information can be extracted such as transport coefficients, phase diagrams, and structural properties.<BR/>Molecular dynamics simulations are typically not memory intensive since only vectors of particles information are stored. Computationally, the simulations are ”large” in two domains - the number of particles and number of time-steps.<BR/>Molecular dynamics computations are inherently parallel. We develop parallel algorithms appropriate for wide class of MD problems with general characteristics:<BR/>• Forces are limited in range, and each particle interacts only with other nearby ones. Granular materials are modeled this way due to short-range interparticle forces. Numerical comlexity per time-step scales as N, the number of particles.<BR/>• Particles can undergo large displacements during the simulation, and each particle’s neighbors change as the simulation prog

Created:2010-05-01
Last updated:2010-05-01