Fluctuation and self-diffusion research about dry granular materials under shearing

Meng, Fanzhong; Meng, Xin; Hua, Shaozhen; Ma, Shuai

doi:10.1007/s40430-019-1663-5

Cited by 5 publications

(4 citation statements)

References 36 publications

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“…They concluded that the fluctuation of a single particle is strongly connected to the system's overall velocity. Similar investigations have been conducted by Meng et al [22], who established that the boundary effect influences the fluctuation of local particles. Lu et al [23] conducted a discrete element simulation of overland flow and demonstrated that there exists a considerable correlation between the dynamic characteristic fluctuation of the particle flow system and the system particle size.…”

Section: Introductionsupporting

confidence: 75%

Effect of Particle Form and Surface Friction on Macroscopic Shear Flow Friction in Particle Flow System

Huang

Wang

2022

Forests

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The damage caused by landslide disasters is very significant. Among them, landslides after forest fires have been widely concerned by scholars in recent years due to their particular physical and chemical properties. This large-scale shear flow of particulate matter has similarities to fluid systems. However, due to the discontinuity of the particle system, its flow process has significant random characteristics. To investigate the random properties of particle systems, this study conducted a series of ring shear tests on four particle systems. The effects of the particle shape, normal stress, and shear velocity on the systems’ shear rheological features were investigated using experimental data. The particle form has an important effect on the macroscopic properties of the system. In a spherical particle system, the macroscopic friction fluctuation is determined by the friction of the particle surface and the system’s normal stress. The shear velocity has a minor effect on this characteristic. Three elements simultaneously influence the macroscopic friction fluctuation of a breccia particle system: the particle surface friction, system normal stress, and shear velocity. The origins of macroscopic frictional fluctuations in particle systems with various shapes are fundamentally distinct. This study contributes to a better understanding of the causes of particle system fluctuations, and establishes the theoretical foundation for the future development of disaster prevention technology.

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Section: Introductionsupporting

confidence: 75%

Effect of Particle Form and Surface Friction on Macroscopic Shear Flow Friction in Particle Flow System

Huang

Wang

2022

Forests

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“…Methods that can be used to display force chains include the pressure sensor detection method [10], the color-sensitive carbon paper indentation method [11], the photoelastic method [6], and the DEM [12]. The DEM is one of the easier methods to realize the distribution of force chains and can obtain content that cannot be obtained through theoretical methods and conventional experiments [13][14][15][16]. Xu et al [17] used the DEM to complete the unloading process of nonsticky soft and sticky hard particles in the moving bed of a simulated flat-bottomed bin.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study on the Optimization of the Material Pressure of the Feeding System

Wang

et al. 2021

Minerals

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To solve the problem of high energy consumption caused by the large initial material pressure of the feeding system, the macroscopic and mesoscopic laws of the effect of the movement of the feeder on the material pressure were studied, and an optimization method of changing the initial position of the feeder to reduce the initial material pressure is proposed. First, the influence of the movement direction of the feeder on the material pressure was studied based on the discrete element method and verified by experiments. A single-factor experiment was designed to analyze the influence of particle size, material repose angle, and bin slope on material pressure, drawing the applicable conditions of the proposed method. On this basis, the influence of the movement state of the feeder on the change of material pressure during the descent process was studied. Then, the motion parameters of the selected feeder descending process were optimized by the response surface method. Finally, case analyses of the vibrating feeding system and the scraper feeding system were carried out. The Discrete Element Method (DEM) calculation results show that the movement of the feeder will cause different distributions and evolution of the force chain on the mesoscale, which will result in different changes in the macroscopic material pressure. The initial material pressure and the material resistance were reduced in the optimized feeding system.

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“…Granules have the characteristics of strong dissipation and insensitivity to high temperature, so that the granular flow lubrication is a perfect fit for these circumstances (Wang et al, 2014a(Wang et al, , 2014bPodgornik et al, 2015). Further studies have shown that hard, dry and cohesionless granules can be used as lubricants to reduce the friction and wear of the friction pairs (Timm et al, 2011;Meng et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Simulations via the discrete element method have advantages of simpler programming language, faster computing speed, having not convergence problem as well as having parallel computing function. Meanwhile, Simulations via the discrete element method can provide a lot of information both at the macroscopic and microscopic levels at any time during simulations, so this enables us to fully evaluate the response results (Meng et al, 2019, Khalilitehrani et al, 2017.…”

Section: Introductionmentioning

confidence: 99%

Constitutive relation and mechanical mechanism analysis in granular lubrication

Meng

Pang

Liu

2019

ILT

Self Cite

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Purpose Granular lubrication can solve some lubrication problems under many extreme operating conditions. Meanwhile, the flow constitutive relation is one of its unsolved problems in fully understanding its rheological mechanism. Design/methodology/approach In this paper, a plane shear cell under granular lubrication is established by the discrete element method to study the flow constitutive relation and its mechanical mechanism of the hard granular lubricants. Findings Research results show that the flow regimes in granular flow lubrication strongly rely on the dimensionless parameter I, in which it is called the inertial coefficient. When the inertial coefficient I increase, the flow regimes of the granular lubricants also evolve from a quasi-static state to a collisional state accordingly. Comparing to the influence of the restitution coefficient, the friction coefficient of the hard granular lubricants has a strong influence on its constitutive relation of the granular flow lubrication. Finally, it is shows that the dimensionless parameter I has strong influence on the contacts and flow states of this granular lubrication system than the influence of the dimensionless parameter R. Originality/value These findings reveal the constitutive relation and mechanical mechanism of granular lubrication and can also offer the helpful reference for the design of the new granular lubrication bearing.

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Fluctuation and self-diffusion research about dry granular materials under shearing

Cited by 5 publications

References 36 publications

Effect of Particle Form and Surface Friction on Macroscopic Shear Flow Friction in Particle Flow System

Effect of Particle Form and Surface Friction on Macroscopic Shear Flow Friction in Particle Flow System

A Numerical Study on the Optimization of the Material Pressure of the Feeding System

Constitutive relation and mechanical mechanism analysis in granular lubrication

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