Numerical simulation of particulate materials using discrete element modelling

Discrete element method (DEM) is a numerical technique pioneered by Cundall for problems in rock mechanics where the continuity between the separate elements does not exist. Discrete numerical simulations with particles are currently used in several different scientific disciplines. The DEM is capable of handling a wide range of material behaviour, inter-body interaction force laws and arbitrary geometries. DEM models granular materials which can freely make and break contacts with their neighbours and is capable of analysing interacting deformable bodies undergoing large absolute or relative motions. DEM-related research has proved to be very meaningful for enhancing the understanding of granular materials. This tool has been used for developing and validating constitutive relationships of particulate materials such as soil, rock, grain or ceramic powder by using appropriate particle properties, sizes, shapes, and gradation. Moreover, DEM is the best tool for explaining the experimentally observed facts from a more fundamental approach. Perhaps one of the major advantages of the discrete particle model approach is that what is being done during a simulation is obvious at all the times. The discrete element model incorporates induced anisotropy, shear dilatancy and stress path dependency from more fundamental principles and has proven its usefulness to generate insights into the processes involved with particulate media. DEM is an explicit finite difference code and because of the explicit nature of the algorithm, it is necessary to use a very small time-step of simulation to guarantee numerical stability and accuracy. Many researchers are attempting to expose the advent of the effective use of the supercomputer and parallel computing for engineering problems by modifying the discrete element simulation codes. This will allow a major step forward in handling a very large number of particles for the more realistic simulations of particulate solids. In this paper, an overview of the discrete element modelling is presented along with some of its applications in engineering.