DEM Simulation of the Granular Compaction Process

2002 ◽  
Author(s):  
Yong Sheng ◽  
C. J. Lawrence ◽  
B. J. Briscoe
Keyword(s):  
Granular Media ◽  
Mechanical Response ◽  
Contact Friction ◽  
Surface Adhesion ◽  
Compaction Process ◽  
Dem Simulation ◽  
Particle Properties ◽  
Granular Compaction ◽  
Continuum Description ◽  
Macroscopic Continuum

In this paper, the discrete element method is employed to simulate the powder compaction process and to produce the detailed results of micro mechanical response in particle scale. The DEM program is capable to calculate the contact between particles considering of surface adhesion, The statistical average properties of the compacts are then obtained from the sum of the particle movements and contacts. The calculated results show that the variation of the particle properties such as contact friction and elastic-plastic contact criteria can significantly affect the bulk response of the assembly. The connection between micro properties of particles and macroscopic continuum description of the behaviour of granular media is then discussed.

DEM Simulation on the Startup Dynamic Process of a Plain Journal Bearing Lubricated by Granular Media

2014 ◽  
Vol 57 (2) ◽  
pp. 198-205 ◽  
Author(s):  
Wei Wang ◽  
Wei Gu ◽  
Kun Liu ◽  
Fei Wang ◽  
Zhanqi Tang
Keyword(s):  
Dynamic Process ◽  
Granular Media ◽  
Journal Bearing ◽  
Dem Simulation

Simulation Study of Granular Compaction Dynamics under Vertical Tapping

2007 ◽  
Vol 555 ◽  
pp. 107-112 ◽  
Author(s):  
D. Arsenović ◽  
S.B. Vrhovac ◽  
Z.M. Jakšić ◽  
Lj. Budinski-Petković ◽  
A. Belić
Keyword(s):  
Numerical Simulation ◽  
Molecular Dynamics ◽  
Friction Coefficient ◽  
Simulation Study ◽  
Material Properties ◽  
Two Dimensions ◽  
Second Phase ◽  
Hard Disks ◽  
Compaction Process ◽  
Granular Compaction

We study by numerical simulation the compaction dynamics of frictional hard disks in two dimensions, subjected to vertical shaking. Shaking is modeled by a series of vertical expansions of the disk packing, followed by dynamical recompression of the assembly under the action of gravity. The second phase of the shake cycle is based on an efficient event−driven molecular−dynamics algorithm. We analyze the compaction dynamics for various values of friction coefficient and coefficient of normal restitution. We find that the time evolution of the density is described by ρ(t)=ρ∞ − ρEα[−(t/τ)α], where Eα denotes the Mittag−Leffler function of order 0<α<1. The parameter τ is found to decay with tapping intensity Γ according to a power law τ ∝ Γ−γ , where parameter γ is almost independent of the material properties of grains. Also, an expression for the grain mobility during compaction process has been obtained.

Numerical Simulation Study on the Failure Mechanism of Bedding Rock Slope Based on the Lagrangian Multiplier Method

2014 ◽  
Vol 513-517 ◽  
pp. 2603-2606
Author(s):  
Fei Yu ◽  
Yu Zhang ◽  
Shan Xiong Chen ◽  
Jian Li
Keyword(s):  
Rock Slope ◽  
Mechanical Response ◽  
Contact Friction ◽  
Lagrangian Multiplier ◽  
Weak Formulation ◽  
Discrete Equations ◽  
Contact Constraint ◽  
The Status ◽  
Lagrangian Multiplier Method ◽  
Bedding Rock Slope

The weak formulation of the Lagrangian control equations considering the contact constraint conditions and the FEM discrete equations have been derived. The non-linear and non-smooth problems of the mechanical response are solved perfectly by adopting the suggestion method for which tolerance large tangential slipping of the contact surface. One excavation bedding rock slope of the Hu-Rong-Xi expressway is analyzed applying the method mentioned above. The distribution rules of the displacement, stress, strain, contact state, contact friction force and sliding distance under the status of critical sliding are obtained. The analysis results indicate that the failure of the bedding slope is a progressive course. The interlayer stagger firstly, then the deformation evaluates to creep bedding slip and the bottom rock occurs buckling slip at last. The destruction model changes form the bedding slide to rock buckling slip.

Discrete Element Method (DEM) Analyses of Hot-Mix Asphalt (HMA) Mixtures Compaction and Internal Structure

2013 ◽  
Vol 639-640 ◽  
pp. 1287-1294 ◽  
Author(s):  
Jing Song Chen ◽  
Lei Zeng ◽  
Jian Yin
Keyword(s):  
Discrete Element Method ◽  
Hot Mix Asphalt ◽  
Coarse Aggregate ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Point Of View ◽  
Compaction Process ◽  
Dem Simulation ◽  
Air Voids ◽  
Superpave Gyratory Compactor

Asphalt mixture compaction is an important procedure of asphalt mixture construction and can significantly affect the performance of asphalt pavement. In this paper, an open source DEM code was applied to simulate the compaction of hot-mix asphalt (HMA) with the Superpave gyratory compactor. The asphalt mixture compaction process, air voids distribution, internal coarse aggregate structure, and the effect of CA ratio were investigated from a microscopic point of view. The analysis results show that DEM simulation is an economical and effective approach to the research of asphalt mixture compaction, and has tremendous potential for asphalt mixture design.

scholarly journals Quantitative Nanomechanical Mapping of Polyolefin Elastomer at Nanoscale with Atomic Force Microscopy

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shuting Zhang ◽  
Yihui Weng ◽  
Chunhua Ma
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Mechanical Response ◽  
Adhesion Force ◽  
Time Dependent ◽  
Surface Adhesion ◽  
Force Microscopy ◽  
Mechanics Model ◽  
Atomic Force ◽  
Force Volume

AbstractElastomeric nanostructures are normally expected to fulfill an explicit mechanical role and therefore their mechanical properties are pivotal to affect material performance. Their versatile applications demand a thorough understanding of the mechanical properties. In particular, the time dependent mechanical response of low-density polyolefin (LDPE) has not been fully elucidated. Here, utilizing state-of-the-art PeakForce quantitative nanomechanical mapping jointly with force volume and fast force volume, the elastic moduli of LDPE samples were assessed in a time-dependent fashion. Specifically, the acquisition frequency was discretely changed four orders of magnitude from 0.1 up to 2 k Hz. Force data were fitted with a linearized DMT contact mechanics model considering surface adhesion force. Increased Young’s modulus was discovered with increasing acquisition frequency. It was measured 11.7 ± 5.2 MPa at 0.1 Hz and increased to 89.6 ± 17.3 MPa at 2 kHz. Moreover, creep compliance experiment showed that instantaneous elastic modulus E1, delayed elastic modulus E2, viscosity η, retardation time τ were 22.3 ± 3.5 MPa, 43.3 ± 4.8 MPa, 38.7 ± 5.6 MPa s and 0.89 ± 0.22 s, respectively. The multiparametric, multifunctional local probing of mechanical measurement along with exceptional high spatial resolution imaging open new opportunities for quantitative nanomechanical mapping of soft polymers, and can potentially be extended to biological systems.

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