Three-dimensional ellipsoidal discrete element modeling of granular materials and its coupling with finite element facets

摘要

Purpose - The purpose of this paper is to develop a discrete element (DE) and multiscale modelingrnmethodology to represent granular media at their particle scale as they interface solid deformablernbodies, such as soil-tool, tire, penetrometer, pile, etc., interfaces.rnDesign/methodology/approach - A three-dimensional ellipsoidal discrete element method (DEM)rnis developed to more physically represent particle shape in granular media while retaining thernefficiency of smooth contact interface conditions for computation. DE coupling to finite element (FE)rnfacets is presented to demonstrate initially the development of overlapping bridging scale methodsrnfor concurrent multiscale modeling of granular media.rnFindings - A closed-form solution of ellipsoidal particle contact resolution and stiffness is presentedrnand demonstrated for two particle, and many particle contact simulations, during gravity deposition,rnand quasi-static oedometer, triaxial compression, and pile penetration. The DE-FE facet couplingrndemonstrates the potential to alleviate artificial boundary effects in the shear deformation regionrnbetween DEM granular media and deformable solid bodies.rnResearch limitations/implications - The research is being extended to couple more robustly thernellipsoidal DEM code and a higher order continuum FE code via overlapping bridging scale methods,rnin order to remove dependence of penetration/shear resistance on the boundary placement for DErnsimulation.rnPractical implications - When concurrent multiscale computational modeling of interfacernconditions between deformable solid bodies and granular materials reaches maturity, modelers willrnbe able to simulate the mechanical behavior accounting for physical particle sizes and flow in therninterface region, and thus design their tool, tire, penetrometer, or pile accordingly.rnOriginality/value - A closed-form solution for ellipsoidal particle contact is demonstrated in thisrnpaper, and the ability to couple DE to FE facets.