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PurposeDevelop a new three‐dimensional discrete element code (BLOKS3D) for efficient simulation of polyhedral particles of any size. The paper describes efficient algorithms for the most important ingredients of a discrete element code.Design/methodology/approachNew algorithms are presented for contact resolution and detection (including neighbor search and contact detection sections), contact point and force detection, and contact damping. In contact resolution and detection, a new neighbor search algorithm called TLS is described. Each contact is modeled with multiple contact points. A non‐linear force‐displacement relationship is suggested for contact force calculation and a dual‐criterion is employed for contact damping. The performance of the algorithm is compared to those currently available in the literature.FindingsThe algorithms are proven to significantly improve the analysis speed. A series of examples are presented to demonstrate and evaluate the performance of the proposed algorithms and the overall discrete element method (DEM) code.Originality/valueLong computational times required to simulate large numbers of particles have been a major hindering factor in extensive application of DEM in many engineering applications. This paper describes an effort to enhance the available algorithms and further the engineering application of DEM.

SUMMARYWith the increasing demand for discrete element simulations with larger number of particles and more realistic particle geometries, the need for efficient contact detection algorithms is more evident. To date, the class of common plane (CP) methods is among the most effective and widely used contact detection algorithms in discrete element simulations of polygonal and polyhedral particles. This paper introduces a new approach to obtain the CP by employing a newly introduced concept of 'shortest link'. Among all the possible line segments that connect any point on the surface of particle A to any point on the surface of particle B, the one with the shortest length defines the shortest link between the two particles. The perpendicular bisector plane of the shortest link fulfils all the conditions of a CP, suggesting that CP can be obtained by seeking the shortest link. A new algorithm, called shortest link method (SLM), is proposed to obtain the shortest link and subsequently the CP between any two polyhedral particles.Comparison of the analysis time between SLM and previously introduced algorithms demonstrate that SLM results in a substantial speed up for polyhedral particles contact detection.

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SUMMARYThe design of earthmoving equipment requires reliable estimates of resisting forces from the soil or rock to be manipulated. A series of discrete element simulations with polyhedral particles designed to replicate a series of bucket-soil interaction experiments are presented. The experiments involve manipulation of a pile of gravel, consisting of angular and sub-rounded particles, with a prototype of a front end loader bucket. The geometry of the soil pile and the trajectory of the bucket from each experiment are simulated using discrete element method (DEM). A single set of DEM model properties, including inter-particle contact friction angle estimated from the initial configuration of the soil pile prior to the start of the experiments, are used for all simulations. The total soil reaction forces acting on the bucket in both horizontal and vertical directions are calculated from each simulation and are compared to measured forces from the corresponding experiment. The results show both qualitative and quantitative agreement between simulations with polyhedral particles and experiments with angular and sub-rounded particles. The major source of discrepancy is attributed to the large particle sizes in the simulation compared to the experiments. Using smaller particles improves the results and provides a better match with the experiments. Other sources of discrepancy are also discussed. The simulations demonstrate that DEM with polyhedral particles can be used to reliably simulate bucket-soil interaction and to estimate force feedback into earthmoving equipment.