Image-based calibration of rolling resistance in discrete element models of sand

Abstract Models that introduce rolling resistance at the contact are widely employed in simulations using discrete element method (DEM) to indirectly represent particle shape effects. This approach offers substantial computational benefits price of increased calibration complexity. work proposes a simplify resistance. The key is an empirical relation between parameter (rolling friction) and 3D grain descriptor (true sphericity). Values true sphericity can be obtained by image analysis grains, either directly acquisition or correlation with simpler-to-obtain 2D measures. Evaluation friction thus made independent from other model parameters. As extra benefit, variability natural sands mapped into model. A mapping calibrated specimen-scale scale results two triaxial compression tests on Hostun sand Caicos ooids. validated different same reference (Ottawa, Ticino). In case Ticino grain-shape 2D, ordinary table scanner. support this direct procedure.