On the Dynamics of Particle-Particle Interaction

Tribology ◽  
2005 ◽  
Author(s):  
W. Cheng ◽  
K. Farhang ◽  
Y. Kwon
Keyword(s):  
Particle System ◽  
Particle Interaction ◽  
Viscoelastic Model ◽  
Approximate Equation ◽  
Conservative System ◽  
Particle Collision ◽  
Elastic Model ◽  
Collision Dynamics ◽  
Interacting Particles ◽  
Jkr Theory

In numerous engineering and science applications understanding the dynamic behavior of two interacting particles plays an indispensable role as it is the foundation based upon which the behavior of a large number of particles may be predicted. When two particles interact, two prominent forces of adhesion and elasticity are at work and, in some respect, in competition. This is especially true when particle-particle collision dynamics is of interest. Upon collision, two particles either develop physical bond, coalesce to form an agglomeration or rebound, each following a distinct path. A promising theory to address particle-particle collision dynamics is due to Johnson, Kendal and Roberts [1] referred to as the JKR method. However, JKR suffers from two main shortcomings in application to particle dynamics. These are (1) implicit relations between force and displacement and (2) representation of a two-particle system as a conservative system. These shortcomings were treated in [2] by first deriving a highly accurate approximate equation based on the JKR theory in which force and displacement are explicitly related and the extension of the JKR theory wherein the Kelving-Voigt viscoelastic model is used instead of the elastic model. This formulation provides an opportunity to study particle-particle collision dynamics, which is the study in the present paper.

scholarly journals A numerical study on droplet-particle collision dynamics

2016 ◽  
Vol 61 ◽  
pp. 499-509 ◽  
Author(s):  
Ilias Malgarinos ◽  
Nikolaos Nikolopoulos ◽  
Manolis Gavaises
Keyword(s):  
Numerical Study ◽  
Particle Collision ◽  
Collision Dynamics

scholarly journals Viscosity and elasticity: a model intercomparison of ice-shelf bending in an Antarctic grounding zone

2017 ◽  
Vol 63 (240) ◽  
pp. 573-580 ◽  
Author(s):  
CHRISTIAN T. WILD ◽  
OLIVER J. MARSH ◽  
WOLFGANG RACK
Keyword(s):  
Young’S Modulus ◽  
Ocean Circulation ◽  
Young's Modulus ◽  
Viscoelastic Model ◽  
Ice Sheet ◽  
Global Ocean ◽  
Elastic Model ◽  
Ice Shelf ◽  
Bending Stresses ◽  
Global Ocean Circulation

ABSTRACTGrounding zones are vital to ice-sheet mass balance and its coupling to the global ocean circulation. Processes here determine the mass discharge from the grounded ice sheet, to the floating ice shelves. The response of this transition zone to tidal forcing has been described by both elastic and viscoelastic models. Here we examine the validity of these models for grounding zone flexure over tidal timescales using field data from the Southern McMurdo Ice Shelf (78° 15′S, 167° 7′E). Observations of tidal movement were carried out by simultaneous tiltmeter and GPS measurements along a profile across the grounding zone. Finite-element simulations covering a 64 d period reveal that the viscoelastic model fits best the observations using a Young's modulus of 1.6 GPa and a viscosity of 1013.7 Pa s (≈ 50.1 TPa s). We conclude that the elastic model is only well-constrained for tidal displacements >35% of the spring-tidal amplitude using a Young's modulus of 1.62 ± 0.69 GPa, but that a viscoelastic model is necessary to adequately capture tidal bending at amplitudes below this threshold. In grounding zones where bending stresses are greater than at the Southern McMurdo Ice Shelf or ice viscosity is lower, the threshold would be even higher.

A Method of Calculating the Dynamic Characteristics of Rubber Isolator

2013 ◽  
Vol 395-396 ◽  
pp. 1170-1173 ◽  
Author(s):  
Xiao Yan Guo ◽  
Jin Zhi Zhou ◽  
Da Peng Feng ◽  
Hou Min Li
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Property ◽  
Excitation Frequency ◽  
Viscoelastic Model ◽  
Elastic Model ◽  
Frequency Dependency ◽  
Plastic Model ◽  
Filled Rubber ◽  
Relative Errors ◽  
Rubber Isolator

The dynamic property of carbon filled rubber materials is related to pre-load, excitation frequency and amplitude etc. A model by superimposing an elastic model, a viscoelastic model and an elastic-plastic model is presented to model the dynamic property of a rubber isolator. In this paper, this approach is adopted to calculate the dynamic property of a rubber isolator. It is shown that the presented model can predict the amplitude and frequency dependency of a rubber isolator with small relative errors. The validity of this model is verified by experiment. The approach described in this paper can be used in the design and calculation for rubber isolators.

scholarly journals Multiscale Simulation of Non-Metallic Inclusion Aggregation in a Fully Resolved Bubble Swarm in Liquid Steel

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 517
Author(s):  
Jean-Sébastien Kroll-Rabotin ◽  
Matthieu Gisselbrecht ◽  
Bernhard Ott ◽  
Ronja May ◽  
Jochen Fröhlich ◽  
...  
Keyword(s):  
Particle Size ◽  
Shear Flow ◽  
Initial Conditions ◽  
Bubbly Flow ◽  
Multiscale Simulation ◽  
Particle Collision ◽  
Immersed Boundary ◽  
Collision Dynamics ◽  
Plane Shear ◽  
Boltzmann Method

Removing inclusions from the melt is an important task in metallurgy with critical impact on the quality of the final alloy. Processes employed with this purpose, such as flotation, crucially depend on the particle size. For small inclusions, the aggregation kinetics constitute the bottleneck and, hence, determine the efficiency of the entire process. If particles smaller than all flow scales are considered, the flow can locally be replaced by a plane shear flow. In this contribution, particle interactions in plane shear flow are investigated, computing the fully resolved hydrodynamics at finite Reynolds numbers, using a lattice Boltzmann method with an immersed boundary method. Investigations with various initial conditions, several shear values and several inclusion sizes are conducted to determine collision efficiencies. It is observed that although finite Reynolds hydrodynamics play a significant role in particle collision, statistical collision efficiency barely depends on the Reynolds number. Indeed, the particle size ratio is found to be the prevalent parameter. In a second step, modeled collision dynamics are applied to particles tracked in a fully resolved bubbly flow, and collision frequencies at larger flow scale are derived.

scholarly journals Plasmon-Enhanced Photothermal and Optomechanical Deformations of a Gold Nanoparticle

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1881
Author(s):  
Jiunn-Woei Liaw ◽  
Guanting Liu ◽  
Yun-Cheng Ku ◽  
Mao-Kuen Kuo
Keyword(s):  
Gold Nanoparticle ◽  
Liquid Layer ◽  
Viscoelastic Model ◽  
Dynamics Simulation ◽  
Photothermal Effect ◽  
Continuous Heating ◽  
Heating Process ◽  
Elastic Model ◽  
Linearly Polarized ◽  
Quasi Liquid Layer

Plasmon-enhanced photothermal and optomechanical effects on deforming and reshaping a gold nanoparticle (NP) are studied theoretically. A previous paper (Wang and Ding, ACS Nano 13, 32–37, 2019) has shown that a spherical gold nanoparticle (NP) irradiated by a tightly focused laser beam can be deformed into an elongated nanorod (NR) and even chopped in half (a dimer). The mechanism is supposed to be caused by photothermal heating for softening NP associated with optical traction for follow-up deformation. In this paper, our study focuses on deformation induced by Maxwell’s stress provided by a linearly polarized Gaussian beam upon the surface of a thermal-softened NP/NR. We use an elastic model to numerically calculate deformation according to optical traction and a viscoelastic model to theoretically estimate the following creep (elongation) as temperature nears the melting point. Our results indicate that a stretching traction at the two ends of the NP/NR causes elongation and a pinching traction at the middle causes a dent. Hence, a bigger NP can be elongated and then cut into two pieces (a dimer) at the dent due to the optomechanical effect. As the continuous heating process induces premelting of NPs, a quasi-liquid layer is formed first and then an outer liquid layer is induced due to reduction of surface energy, which was predicted by previous works of molecular dynamics simulation. Subsequently, we use the Young–Laplace model to investigate the surface tension effect on the following deformation. This study may provide an insight into utilizing the photothermal effect associated with optomechanical manipulation to tailor gold nanostructures.

Structure Formation of Sulfur-Based Composite: The Model

2014 ◽  
Vol 1040 ◽  
pp. 592-595 ◽  
Author(s):  
Denis G. Kiselev ◽  
Evgeniy Valerjevich Korolev ◽  
Vladimir Smirnov
Keyword(s):  
Boundary Layer ◽  
Particle System ◽  
Particle Interaction ◽  
Numerical Algorithms ◽  
Binary Interaction ◽  
Environment Interaction ◽  
Simultaneous Application ◽  
Numerical Studies ◽  
Key Factor ◽  
The Law

In material science the simultaneous application of theoretical examination, experimental and numerical studies are often required. This is especially true for modern composite materials with extra inter-boundary nanoscale layers. Thickness of layers is usually about tens of nanometers, while diameters of particles of filler are about several hundreds of nanometers. Thus, during the theoretical study and numerical experiments the size and properties of inter-boundary layer must be taken into account. The proper choice of the model is the key factor for the adequate results of simulation. In the present work we have derived such a model. The system under investigation – disperse-filled composite material with inter-boundary layers of different properties – is represented by particle system; these classes of models can be characterized by high generality. Initial equation for the law of motion is sequentially extended with terms which account for different phenomena – conservative binary interaction, non-conservative interaction with environment, interaction with planar boundaries and non-conservative particle-particle interaction via inter-boundary layer. The reduction of the law of motion to the system of ordinary differential equations had opened the possibility for utilization of the vast majority of numerical algorithms for the prediction of the structural properties of nanomodified sulfur-based composite.

Review of advances in micromechanical modeling of aggregate–aggregate interactions in asphalt mixtures

2007 ◽  
Vol 34 (2) ◽  
pp. 239-252 ◽  
Author(s):  
Zhanping You ◽  
Qingli Dai
Keyword(s):  
Finite Element ◽  
Particle Interaction ◽  
Asphalt Mixture ◽  
Complex Mixture ◽  
Element Model ◽  
Laboratory Simulation ◽  
Micromechanical Modeling ◽  
Discrete Elements ◽  
Interacting Particles ◽  
Work Done

This paper presents a comprehensive review of the work done by a number of researchers on the modeling of asphalt mixture. Included are some of the earliest models such as those with non-interacting particles (models with and without geometry specified), models with particle interaction, and some new models developed in recent years. The paper focuses on the description and comparison of the most recently developed finite element network model (FENM), a clustered discrete element model (DEM), and a micromechanical finite element model (FEM) used in micromechanical modeling of asphalt mixture. These models consider the complex mixture microstructure and aggregate–aggregate interaction. These models are demonstrated and applications of the advances are provided, where virtual laboratory simulation and laboratory tests were employed. The feasibility of nanotechnology application in asphalt mixture is also briefly discussed.Key words: micromechanical modeling, micromechanics, aggregate–aggregate interaction, finite elements, discrete elements, asphalt mixture.

Microstructure Of Fe-Nd-B Alloys Tailored To Approach Theoretical Coercrvtty Limits

1999 ◽  
Vol 5 (S2) ◽  
pp. 26-27
Author(s):  
Kannan M. Krishnan ◽  
Er. Girt ◽  
E. C. Nelson ◽  
G. Thomas ◽  
Ferdinand Hofer
Keyword(s):  
Magnetic Particles ◽  
Permanent Magnets ◽  
Spontaneous Magnetization ◽  
Particle Interaction ◽  
Maximum Energy ◽  
Interacting Particles ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Oriented Samples ◽  
The Difference

Performance of permanent magnets for a variety of applications is often determined by the maximum energy product (BH)max. In order to obtain high (BH)max permanent magnetic materials have to have large coercivity. In theory the coercive field of ideally oriented, non-interacting, single domain, magnetic particles, assuming Kl is much bigger than K2, was shown to be He = 2K1/Ms - N Ms, where Kl and K2 are the magnetocrystalline anisotropy constants, Ms is the spontaneous magnetization and N is the demagnetization factor. For randomly oriented non-interacting particles the Stoner-Wohlfarth model predicts that the value of Hc decreases to about half. However, experimentally obtained values of the coercitive fields in permanent magnets are 3 to 10 and 2 times smaller for well oriented and randomly oriented samples, respectively. This discrepancy was attributed to inter-particle interaction and the microstructure of the permanent magnets. In order to understand the difference between the theoretically predicted and experimentally obtained results for He we prepared rapidly quenched, Nd-rich, NdxFe14B (2 < x < 150) ribbons.

Sign in / Sign up

Export Citation Format

Share Document