Contact parameter estimation for DEM simulation of iron ore pellet handling

The appropriate choice of contact parameters is of great importance, particularly when simulations using the discrete element method (DEM) are run with the aim of capturing quantitative information on collision events that occur among the individual particles, as what happens during handling of iron ore pellets. The paper analyzes the use of tests conducted with single pellets for estimating material and contact parameters that are required in DEM simulations using the no-slip Hertz-Mindlin model. Tests included impact load cell, tribometer, drop tests and a simple test in which the rolling angle of individual pellets is measured. It is concluded that, provided particle shapes are described appropriately, DEM simulations provide reasonably realistic predictions of pellet motion in assemblies from contact parameters measured on the basis of single-particle tests. In this case the physical significance of the contact parameters is maintained. However, if pellets are described in a simplistic way as spheres, then the DEM simulation of their flow no longer matches the experimental results, requiring fitting some of the contact parameters in order to match the observed global flow, so that much of the physical meaning of the parameters is lost. (C) 2013 Elsevier B.V. All rights reserved.