arXiv subjects

Fei-Liang Yuan

Publications and source records attributed to Fei-Liang Yuan.

3 recordsLinked to original sources

arXiv2024

SR-DEM: an efficient discrete element method for particles with surface of revolution

In this paper, the surface of revolution discrete element method (SR-DEM) is introduced to simulate systems of particles with closed surfaces of revolution. Due to the cylindrical symmetry of a surface of revolution, the geometry of any cross-section about the axis of rotation remains the same. Taking advantage of this geometric feature, a node-to-cross-section contact algorithm is proposed for efficient contact detection between particles with a surface of revolution. In our SR-DEM framework, the contact algorithm is realized in a master-slave fashion: the master particle is approximated by its surface nodes, while the slave particle is represented by a signed distance field (SDF) of the cross-section about the axis of rotation. This hybrid formulation in both 2D and 3D space allows a very efficient contact calculation yet relatively simple code implementation. We then apply SR-DEM to simulate particle-particle, particle-wall impact, granular packing in a cylindrical container, and tablets in a rotating drum, to demonstrate SR-DEM's ability to predict the post-impact velocities, packing porosity, and dynamic angle of repose, respectively. Finally, we suggest a simple approach to find an optimal surface resolution, by increasing the number of surface nodes until some of the bulk properties that could characterize the system converge.

cs.CE↗

arXiv2024

Multi-sphere approximation of realistic particles with a combined 3D thinning and greedy algorithm

This article is the updated version of the paper: "Combined 3D thinning and greedy algorithm to approximate realistic particles with corrected mechanical properties, Granular Matter (2019)" by the first author [58]. The main changes here are (1) a recently developed DEM code Rigid3D is used for the DEM simulations, instead of the open-source software LIGGGHTS in the original work; (2) three new validation tests were carried out. The main idea of this work is to combine the 3D thinning and greedy set-covering algorithms for the approximation of realistic particles with multiple spheres. First, the particle's medial surface (or surface skeleton), from which all candidate (maximal inscribed) spheres can be generated, is computed by the topological 3D thinning algorithm. Then, the clump generation procedure is converted into a greedy set-covering problem. The advantage of this approach over previous studies is that, with a given particle media surface and a grid resolution for the discretized particle, a minimum number of component (or primary) spheres for an MS particle is guaranteed for a maximum volume coverage, thanks to the combined algorithm. To correct the mass distribution of an MS particle due to the highly overlapped component spheres, linear programming (LP) is used to adjust the density of each component sphere, such that the aggregate properties such as mass, center of mass, and inertia tensor are identical or close enough to the prototypical particle. We then demonstrate the capability of the combined algorithm to approximate simple to complex particle shapes in three test cases: (1) particle-wall contact; (2) particle settling; and (3) granular flow in a rotating drum.

physics.app-ph↗

arXiv2023

Rigid3D: a hybrid multi-sphere DEM framework for simulation of non-spherical particles in multi-phase flow

This article presents the development and validation of a hybrid multi-sphere discrete element framework - Rigid3D, for the simulation of granular systems with arbitrarily shaped particles in 3D space. In this DEM framework, a non-spherical particle is approximated by three different geometric models: (1) multi-sphere model with overlapping spheres (MS model), (2) particle surface with triangle mesh (surface model), and (3) discretized particle body with polyhedral cells (cell model). The multi-sphere approach will be the "engine" for efficient DEM simulations, while the particle's mesh and cell models will be updated simultaneously according to the position and orientation of their associated MS model, for use in particle-related inter-phase couplings in a multi-phase flow. In this sense, Rigid3D tries to combine the best of both worlds in multi-sphere and polyhedral DEMs: multi-sphere method for the efficiency and acceptable accuracy in the DEM simulation of granular flows, while the surface and cell models for the couplings between particles and other phases (continuous or dispersed phases) without affecting the performance of DEM simulations.

cs.CE↗