Calibration of DEM Parameters

This chapter summarises different Discrete Element Modelling (DEM) calibration philosophies, the most important DEM parameters of the most commonly used contact models, and different calibration tests to determine the DEM parameters efficiently and unambiguously. While only a very brief overview about the basic function and principle of the DEM is given, the focus of the chapter is on the calibration of non-cohesive materials for bulk handling applications under relatively low consolidation pressures (typically less than 10 kPa). The methods to calibrate granular materials under these conditions have reached such a level of maturity that it can be applied with confidence. This includes, but is not limited to, natural materials such as gravel, crushed rock particles, sand, ore such as iron ore and coal ore, and agricultural grains such as corn and wheat. Applications include the flow through conveyor transfer chutes, in and out of silos, hoppers, and bins. When these materials are wet, they become cohesive, which significantly alters the material behaviour. The calibration and validation of DEM models for modelling of cohesive materials have not yet reached the same level of maturity as for non-cohesive materials. For this reason, some aspects of the modelling of cohesive materials are addressed, but this should not be seen as comprehensive. Finally, a summary of optimisation algorithms is presented. These algorithms are used to improve the efficiency of the calibration process and to handle the increasing complexity of cohesive bulk materials with multiple parameters.