Special Issue "Computational Mechanics of Granular Materials and its Engineering Applications"

Submission Deadline: 31 January 2021 (closed)
Guest Editors
Prof. Shunying Ji, Dalian University of Technology, China
Prof. Michael Zhuravkov, Belarusian State University, Belarus
Dr. Zongyan Zhou, Monash University, Australia
Prof. Yuntian Feng, Swansea University, UK

Summary

Granular materials exist widely in nature or industrial production, and form complex granular systems with structures. A granular system has complex mechanical properties of solid or liquid, and quasi-solid-liquid transition may occur under certain conditions. The discrete element method (DEM) was proposed in 1979 and has been shown to be a practical tool for studying the macro and mesoscopic behaviors of various granular materials. In this approach, the particle shape strongly affects the granular packing, dynamic responses, and flow processes of granular materials. Moreover, the conclusions obtained from spherical systems are difficult to apply directly to non-spherical systems. During the flow process, the particles may be rearranged to form an arch structure. The adjacent particles contact with each other to form a force chain structure of varying strength, so that the granular flow is changed from a dense state to a blocked state. Although DEM has been successfully applied to the study of basic physical and mechanical properties of granular materials, there are still many challenges in computational granular mechanics, such as the construction of real particle morphology, flow pattern transition of granular materials, multi-media and multi-scale contact model, force chain network within the granular system, and high-performance parallel algorithm.

The aim of this special issue is to bring together the latest advances in computational mechanics and engineering applications of granular materials, with particular emphasis on the theoretical constructions of arbitrarily shaped particles, flow pattern transitions, GPU parallel algorithms, and multi-scale and multi-media models, and to improve our understanding of granular systems in view of large scale and practical engineering applications.


Keywords
Granular materials, the discrete element method, contact force model, force chain

Published Papers
  • DEM Simulations of Resistance of Particle to Intruders during Quasistatic Penetrations
  • 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 and the rules pertaining to… More
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  • Deep Learning Predicts Stress–Strain Relations of Granular Materials Based on Triaxial Testing Data
  • Abstract This study presents an AI-based constitutive modelling framework wherein the prediction model directly learns from triaxial testing data by combining discrete element modelling (DEM) and deep learning. A constitutive learning strategy is proposed based on the generally accepted frame-indifference assumption in constructing material constitutive models. The low-dimensional principal stress-strain sequence pairs, measured from discrete element modelling of triaxial testing, are used to train recurrent neural networks, and then the predicted principal stress sequence is augmented to other high-dimensional or general stress tensor via coordinate transformation. Through detailed hyperparameter investigations, it is found that long short-term memory (LSTM) and gated recurrent… More
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  • Analysis of One-Dimensional Compression under a Wide Range of Stress with Densely Arrayed BPM
  • Abstract In this paper, the densely arrayed bonded particle model is proposed for simulation of granular materials with discrete element method (DEM) considering particle crushing. This model can solve the problem of pore calculation after the grains are crushed, and reduce the producing time of specimen. In this work, several one-dimensional compressing simulations are carried out to investigate the effect of particle crushing on mechanical properties of granular materials under a wide range of stress. The results show that the crushing process of granular materials can be divided into four different stages according to er-logσy curves. At the end of the… More
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  • Discrete Particle Simulation of Gas-Solid Flow in Air-Blowing Seed Metering Device
  • Abstract In this paper, the gas and seed flow characters in the air-blowing seed metering device are investigated by using the coupled computational fluid dynamics and discrete element method (CFD-DEM) in three dimensions (3D). The method of establishing boundary model based on the computer-aided design (CAD) drawing, has been used to build the boundary model of seed metering device. The 3D laser scanning technique and multi-element method are adopted to establish the particle model. Through a combined numerical and experimental effort, using 3D CFD-DEM software, which is based on the in-house codes, the mechanisms governing the gas and solid dynamic behaviors… More
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  • Comparison of Coarse Graining DEM Models Based on Exact Scaling Laws
  • 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 for the size of particles… More
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