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 >

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 >

Huinan Sun^1,*, 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 >

Bin Zhang^1,2, Yiming Huang^3,4, Tingting Zhao^5,*

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 >

Tingting Zhao¹, Y. T. Feng^2,*, 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 >

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 >

Yatin Suri¹, Sheikh Zahidul Islam^{1, *}, 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 >

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 >

Letícia Fleck Fadel Miguel¹, Leandro Fleck Fadel Miguel², João Kaminski Jr.³

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.2, pp. 87-104, 2015, DOI:10.3970/cmes.2015.104.086

Abstract Since the half of the XX century, attention was given to the instability of structures under parametric excitation, especially under periodic loads. On the other hand, the instability of bars subjected to axial loads of impulsive type has been little studied, in spite of the practical importance of the topic. Thus, in Engineering Design it is frequently supposed, without tests or additional verifications, that an axial load of short duration can exceed the Euler critical load of the bar without inducing damage in the same.
Within this context, this paper proposes the use of the… More >

Eduardo M. B. Campello^1,2, Tarek I. Zohdi³

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.2, pp. 221-245, 2014, DOI:10.3970/cmes.2014.098.221

Abstract This work deals with the bombardment of a stream of particles possessing varying mean particle size, velocity and aspect ratio into a cell that has fixed (known) compliance characteristics. The particles are intended to penetrate the cell membrane causing zero or minimum damage and deliver foreign substances (which are attached to their surfaces) to the interior of the cell. We adopt a particle-based (discrete element method) computational model that has been recently developed by the authors to describe both the incoming stream of particles and the cell membrane. By means of parametric numerical simulations, treating… More >