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  • Open Access

    ARTICLE

    A Consistent Time Level Implementation Preserving Second-Order Time Accuracy via a Framework of Unified Time Integrators in the Discrete Element Approach

    Tao Xue1, Yazhou Wang2, Masao Shimada2, David Tae2, Kumar Tamma2,*, Xiaobing Zhang1,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 1469-1487, 2023, DOI:10.32604/cmes.2022.021616 - 20 September 2022

    Abstract In this work, a consistent and physically accurate implementation of the general framework of unified second-order time accurate integrators via the well-known GSSSS framework in the Discrete Element Method is presented. The improved tangential displacement evaluation in the present implementation of the discrete element method has been derived and implemented to preserve the consistency of the correct time level evaluation during the time integration process in calculating the algorithmic tangential displacement. Several numerical examples have been used to validate the proposed tangential displacement evaluation; this is in contrast to past practices which only seem to… More >

  • Open Access

    ARTICLE

    Discrete Element Simulations of Ice Load and Mooring Force on Moored Structure in Level Ice

    Hongri Zhu, Shunying Ji*

    CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.1, pp. 5-21, 2022, DOI:10.32604/cmes.2022.019991 - 02 June 2022

    Abstract Moored structures are suitable for operations in ice-covered regions owing to their security and efficiency. This paper aims to present a new method for simulating the ice load and mooring force on the moored structure during ice-structure interaction with a spherical Discrete Element Method (DEM). In this method, the level ice and mooring lines consist of bonded sphere elements arranged in different patterns. The level ice model has been widely validated in simulation of the ice load of fixed structures. In the mooring line simulation, a string of spherical elements was jointed with the parallel… More >

  • Open Access

    ARTICLE

    Numerical Analysis of Ice Rubble with a Freeze-Bond Model in Dilated Polyhedral Discrete Element Method

    Biyao Zhai, Lu Liu, Shunying Ji*

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.1, pp. 1-22, 2022, DOI:10.32604/cmes.2022.018652 - 29 November 2021

    Abstract Freezing in ice rubble is a common phenomenon in cold regions, which can consolidate loose blocks and change their mechanical properties. To model the cohesive effect in frozen ice rubble, and to describe the fragmentation behavior with a large external forces exerted, a freeze-bond model based on the dilated polyhedral discrete element method (DEM) is proposed. Herein, imaginary bonding is initialized at the contact points to transmit forces and moments, and the initiation of the damage is detected using the hybrid fracture model. The model is validated through the qualitative agreement between the simulation results More >

  • Open Access

    ARTICLE

    DEM Simulations of Resistance of Particle to Intruders during Quasistatic Penetrations

    Shaomin Liang, Lu Liu, Shunying Ji*

    CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.1, pp. 145-160, 2021, DOI:10.32604/cmes.2021.016403 - 28 June 2021

    Abstract Based on the discrete element method and hydrostatics theory, an improved Archimedes principle is proposed to study the rules pertaining to resistance changes during the penetration process of an intruder into the particulate materials. The results illustrate the fact that the lateral contribution to the resistance is very small, while the tangential force of the lateral resistance originates from friction effects. Conversely, the resistance of particulate materials on the intruder mainly occurs at the bottom part of the intruding object. Correspondingly, the factors that determine the resistance of the bottom part of the intruding object… More >

  • Open Access

    ARTICLE

    Flow Characteristics of Grains in a Conical Silo with a Central Decompression Tube Based on Experiments and DEM Simulations

    Huinan Sun1,*, Siqiang Wang2, Zhuoqing Zhang1, Chaoyong Xia1, Xu Chen1

    CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.3, pp. 855-873, 2021, DOI:10.32604/cmes.2021.015791 - 24 May 2021

    Abstract Grains are widely present in industrial productions and processing, and are stored in silos. In the silo, auxiliary structures are added to achieve efficient production. However, little effort has been devoted to the influence of the internal structure of the silo on the granular flow. In this work, a silo with a central decompression tube is studied through experimental measurements and discrete element methods. Then, the influences of the central decompression tube on the flow behavior of grains and wall pressure are analyzed. Results show that the grains are in mass flow in the silo… More >

  • Open Access

    ARTICLE

    Comparison of Coarse Graining DEM Models Based on Exact Scaling Laws

    Bin Zhang1,2, Yiming Huang3,4, Tingting Zhao5,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.3, pp. 1133-1150, 2021, DOI:10.32604/cmes.2021.016018 - 24 May 2021

    Abstract The simulation of a large number of particles requires unacceptable computational time that is the most critical problem existing in the industrial application of the DEM. Coarse graining is a promising approach to facilitate the application of DEM to industrial problems. While the current coarse graining framework is often developed in an ad-hoc manner, leading to different formulations and different solution accuracy and efficiency. Therefore, in this paper, existing coarse graining techniques have been carefully analysed by the exact scaling law which can provide the theory basis for the upscaling method. A proper scaling rule More >

  • Open Access

    ARTICLE

    Discrete Element Modelling of Dynamic Behaviour of Rockfills for Resisting High Speed Projectile Penetration

    Tingting Zhao1, Y. T. Feng2,*, Jie Zhang1, Zhihua Wang1, Zhiyong Wang1

    CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.2, pp. 721-735, 2021, DOI:10.32604/cmes.2021.015913 - 19 April 2021

    Abstract This paper presents a convex polyhedral based discrete element method for modelling the dynamic behaviour of rockfills for resisting high speed projectile penetration. The contact between two convex polyhedra is defined by the Minkowski overlap and determined by the GJK and EPA algorithm. The contact force is calculated by a Minkowski overlap based normal model. The rotational motion of polyhedral particles is solved by employing a quaternion based orientation representation scheme. The energy-conserving nature of the polyhedral DEM method ensures a robust and effective modelling of convex particle systems. The method is applied to simulate… More >

  • Open Access

    ARTICLE

    Discrete Element Simulation of Asphalt Pavement Milling Process to Improve the Utilization of Milled Old Mixture

    Jianmin Wu*, Bingbing Zhang, Chunsheng Wu, Zhiqiang Shu, Shaoqing Li, Jianqi Yang

    Journal of Renewable Materials, Vol.9, No.5, pp. 993-1011, 2021, DOI:10.32604/jrm.2021.014304 - 20 February 2021

    Abstract In order to improve the utilization of milling materials, save stone resources and reduce milling energy consumption, the aged Styrene-butadiene-styrene (SBS) modified asphalt was used as a binder to prepare AC-16 asphalt mixture to simulate old asphalt pavement materials. First, the test and discrete element simulation results of uniaxial compression tests were used to calibrate the parameters of the parallel bonding contact model between asphalt mortar and aggregates. On this basis, a microscopic model of the asphalt mixture was established to simulate the old asphalt pavement. Then, the discrete element software PFC (Particle Flow Code)… More >

  • Open Access

    ARTICLE

    Numerical Modelling of Proppant Transport in Hydraulic Fractures

    Yatin Suri1, Sheikh Zahidul Islam1, *, Mamdud Hossain1

    FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 297-337, 2020, DOI:10.32604/fdmp.2020.08421 - 21 April 2020

    Abstract The distribution of proppant injected in hydraulic fractures significantly affects the fracture conductivity and well performance. The proppant transport in thin fracturing fluid used during hydraulic fracturing in the unconventional reservoirs is considerably different from fracturing fluids in the conventional reservoir due to the very low viscosity and quick deposition of the proppants. This paper presents the development of a threedimensional Computational Fluid Dynamics (CFD) modelling technique for the prediction of proppant-fluid multiphase flow in hydraulic fractures. The proposed model also simulates the fluid leak-off behaviour from the fracture wall. The Euler-Granular and CFD-Discrete Element… More >

  • Open Access

    ABSTRACT

    Flow Characteristics of Non-Spherical Particles Simulated with Super-Quadric DEM

    Shunying Ji*, Siqiang Wang

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.1, pp. 94-94, 2019, DOI:10.32604/icces.2019.04805

    Abstract Granular flow is commonly encountered in industry or nature, and is significantly affected by particle shapes. Super-quadric particles which can construct the geometric shape of irregular particles are simulated by the Discrete Element Method (DEM). In this study, the influence of aspect ratio and blockiness of particles on the flow characteristics is investigated, and the different discharge angles are used for different shaped particles to show the superposed effect of hopper configuration. Meanwhile, the Lacey mixing index is used to explore the effects of particle shapes on the mixing and motion of the granular system… More >

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