Numerical Modelling

On the linear elastic responses of the 2D bonded discrete element model

Abstract

The bonded Discrete Element Model (DEM) is anumerical tool that is becoming widely used when studying fracturing,fragmentation and failure of solids in various disciplines. However, itsabilities to solve elastic problems are usually overlooked. In this work, the mainfeatures of the bonded DEM which influence Poisson’s ratio and Young’s modulus,and accuracy when solving elastic boundary value problems, are investigated.Outputs of numerical simulations using the bonded DEM, the Finite ElementMethod (FEM), a hyper elasticity analysis and the Distinct Lattice Spring Model(DLSM) are compared in the investigation. It is shown that a shear interaction(local) factor and a geometric (global) factor are two essential elements forthe bonded DEM to reproduce a full range of Poisson’s ratios. It is also foundthat the bonded DEM might be unable to reproduce the correct displacements forelastic boundary value problems when the represented Poisson’s ratio is closeto 0.5 or the long-range interaction is considered. In addition, an analytical relationshipbetween the shear stiffness ratio and the Poisson’s ratio, derived from a hyperelasticity analysis and applicable to discontinuum based models, provides goodagreement with outputs from the bonded DEM and DLSM. Finally, it is shown thatthe selection of elastic parameters used the bonded DEM has a significanteffect on fracturing and fragment patterns of solids.


Keywords: Discreteelement model; Poisson’s ratio; Hyper elasticity analysis; Fracturing;Fragmentation


Bonded DEM.jpg

Bonded DEM