Multiscale simulations of the mechanical behaviour of an ensiled granular material

Discrete simulations by the distinct element method are performed for modelling an ensiled granular material. Starting from the material microstructure on a microscopic scale, two procedures are considered in order to simulate the mechanical behaviour of the material within a silo on a megascopic scale. On the one hand, a direct discrete simulation from the microscopic scale to the megascopic scale is carried out. On the other hand, a two-step simulation procedure is performed: the determination of the macroscopic behaviour from the microscopic scale, followed by a continuum analysis from the macroscopic scale to the megascopic scale. The macroscopic parameters are derived from discrete simulations of usual rheological tests. An experimental validation of the distinct element method is presented by simulating a biaxial compression test. The macroscopic parameters of the ensiled material are then identified and introduced into a finite element analysis with an elastic–plastic constitutive model using the Mohr–Coulomb criterion. The results of the two above procedures are compared and in this way the relevance of the discrete simulation is demonstrated. Copyright © 2000 John Wiley & Sons, Ltd.