UC Pavement Research Center, Sustainable Transportation Center
Available online at doi: 10.1002/nme.3254
Fu, Pengcheng, Otis R. Walton, John T. Harvey (2012) Polyarc Discrete Element for Efficiently Simulating Arbitrarily Shaped 2D Particles. International Journal for Numerical Methods in Engineering 89 (5), 599 - 617
A new two-dimensional discrete element type, termed the ‘polyarc’ element is presented in this paper. Compared to other discrete element types, the new element is capable of representing any two-dimensional convex particle shape with arbitrary angularity and elongation using a small number of shape parameters. Contact resolution between polyarc elements, which is the most computation-extensive task in DEM simulation only involves simple closed-form solutions. Two undesirable contact scenarios common for polygon elements can be avoided by the polyarc element, so the contact resolution algorithm for polyarc elements is simpler than that for polygon elements. The extra flexibility in particle shape representation induces little or no additional computational cost. The key algorithmic aspects of the new element, including the particle shape representation scheme, the quick neighbor search algorithm, the contact resolution algorithm, and the contact law are presented. The recommended contact law for the polyarc model was formulated on the basis of an evaluation of various contact law schemes for polygon type discrete elements. The capability and efficiency of the new element type were demonstrated through an investigation of strength anisotropy of a virtual sand consisting of a random mix of angular and smooth elongated particles subjected to biaxial compression tests.
Keywords: discrete element; contact law; granular material; fabric anisotropy; strength anisotropy