Effects of Interfacial Zone Percolation on Cement-Based Composite Transport Properties

1991 ◽  
Vol 245 ◽  
Author(s):  
K.A. Snyder ◽  
D.N. Winslow ◽  
D.P. Bentz ◽  
E.J. Garboczi
Keyword(s):  
Computer Simulation ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Transport Properties ◽  
Volume Fraction ◽  
Cement Mortar ◽  
Mercury Porosimetry ◽  
Computer Simulation Model ◽  
Interfacial Zone ◽  
Aggregate Particles

ABSTRACTIn portland cement mortar and concrete, interfacial zones exist around the aggregate particles that have larger pore sizes and pore volumes than the bulk cement paste. If there are enough aggregate particles present, these zones may overlap so as to percolate. A computer simulation model has been developed that can predict this percolation point as a function of interfacial zone thickness, volume fraction of aggregates, and aggregate particle size distribution. The model was used to simulate 1cm3 of mortar, using approximately 10,000 aggregate particles. Results from this model are used to explain recent mercury porosimetry results on mortars having a variety of sand contents. The implications of interfacial zone percolation for the transport properties of mortar and concrete are discussed.

scholarly journals Monte Carlo simulation for soot dynamics

2012 ◽  
Vol 16 (5) ◽  
pp. 1391-1394 ◽  
Author(s):  
Kun Zhou
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Phase ◽  
Volume Fraction ◽  
Soot Formation ◽  
Bimodal Distribution ◽  
Number Density ◽  
Stochastic Error

A new Monte Carlo method termed Comb-like frame Monte Carlo is developed to simulate the soot dynamics. Detailed stochastic error analysis is provided. Comb-like frame Monte Carlo is coupled with the gas phase solver Chemkin II to simulate soot formation in a 1-D premixed burner stabilized flame. The simulated soot number density, volume fraction, and particle size distribution all agree well with the measurement available in literature. The origin of the bimodal distribution of particle size distribution is revealed with quantitative proof.

Computer Simulation Model for Spherical Particle Filled Composite Materials

2011 ◽  
Vol 474-476 ◽  
pp. 7-10 ◽  
Author(s):  
Zhuo Chen ◽  
Zhi Xiong Huang ◽  
Ming Zhang ◽  
Min Xian Shi ◽  
Yan Qin ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Composite Materials ◽  
Simulation Model ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Spherical Particles ◽  
Computer Simulation Model ◽  
Particle Volume ◽  
Minimal Sphere ◽  
Center Density

This paper introduced a computer simulation model for composite materials which was reinforced by spherical particles. We introduced its algorithm and visualize the model with different particle volume fraction. In order to evaluate the uniformity of the particle distribution, we estimated Particle Center Density and standard deviation of minimal sphere distance.

Hall-Petch Relation in a Spheroidized Carbon Steel with Emphasis on the Effect of Intergranular Particles

2016 ◽  
Vol 848 ◽  
pp. 593-606 ◽  
Author(s):  
Jiang Li Ning ◽  
Yun Li Feng ◽  
Jie Li
Keyword(s):  
Particle Size ◽  
Carbon Steel ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Volume Fraction ◽  
Quantitative Relationship ◽  
Medium Carbon Steel ◽  
Orientation Factor ◽  
Triple Junctions ◽  
Petch Relation

The Hall-Petch relation in a spheroidized steel with bimodal cementite particle size distribution has been investigated in this study, with an emphasis on considering the effect of the large particles at ferrite grain boundaries and triple junctions. A medium carbon steel was processed by variable thermomechanical procedures to achieve spheroidized structures with different combinations of microstructrual parameters, but all exhibiting a bimodal particle size distribution, in which large intergranular particles and small intragranular particles coexisted in the ferrite matrix. A quantitative relationship between the Hall-Petch parameter ky and the volume fraction of the intergranular cementite particles is presented, by considering a composite model. The contribution of the large intergranular particles to grain boundary strengthening wa substantiated by the increment of the ky parameter, since the average orientation factor of the composite, is increased. After correction of the ky parameters based on the constants from literatures, the predicted stresses show good agreement with the experimental stresses. A linear fit between the experimental stresses and the reciprocal square root of grain sizes is performed, the slope constant ky derived agrees to within 11 % of the corrected ky parameters based on the constants from literatures.

Computer Simulation of Electrorheological Fluids in the Binary System of Particle Size

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1822-1827
Author(s):  
Yasushige Mori ◽  
Tetsu Tsunamoto ◽  
Hitoshi Nakayama
Keyword(s):  
Computer Simulation ◽  
Particle Size ◽  
Shear Stress ◽  
Fine Particles ◽  
Volume Fraction ◽  
Dielectric Polarization ◽  
Uniform Size ◽  
Polarization Model ◽  
Effect Of Particle Size ◽  
Er Fluids

One of the typical electrorheological (ER) fluids consists of suspension of fine particles in the liquid of low dielectric constant. Particles for ER fluids generally have a size distribution, and some experimental results were reported which showed the effect of particle size on the shear stress of ER fluids. On the other hand, the simulation by dielectric polarization model concluded that the shear stress calculated did not depend on the particle size under the same volume fraction of particles. In order to understand the effect of particle size, the two dimensional computer simulation was carried out for a system containing particles of different size, by using a model similar to that reported by Klingenberg et al. It was found that the shear stress of uniform size system did not depend on the particle size. When small and large particles, with the diameter ratio of 1:2, were mixed in equal numbers of particles, the chain-like clusters consisiting of both sizes of particles were formed. The shear stress and the response time of the binary size system were close to those of uniform size system, if the total volume fraction of particles was kept constant.

Simulating Phase Coarsening of Ultra-High Volume Fractions

2010 ◽  
Vol 638-642 ◽  
pp. 3925-3930 ◽  
Author(s):  
K.G. Wang ◽  
X. Ding
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Volume Fraction ◽  
High Volume ◽  
Triple Junctions ◽  
Ginzburg Landau ◽  
Volume Fractions ◽  
Phase Coarsening ◽  
Kinetics Of

The dynamics of phase coarsening at ultra-high volume fractions is studied based on two-dimensional phase-field simulations by numerically solving the time-dependent Ginzburg-Landau and Cahn-Hilliard equations. The kinetics of phase coarsening at ultra-high volume fractions is discovered. The microstructural evolutions for different ultra-high volume fractions are shown. The scaled particle size distribution as functions of the dispersoid volume fraction is presented. The particle size distribution derived from our simulation at ultra-high volume fractions is close to Wagner's particle size distribution due to interface-controlled ripening rather than Hillert's grain size distribution in grain growth. The changes of shapes of particles are carefully studied with increase of volume fraction. It is found that more liquid-filled triple junctions are formed as a result of particle shape accommodation with increase of volume fraction at the regime of ultra-high volume fraction.

A GENERALIZED KINETIC MODEL OF SEDIMENTATION OF POLYDISPERSE SUSPENSIONS WITH A CONTINUOUS PARTICLE SIZE DISTRIBUTION

2008 ◽  
Vol 18 (10) ◽  
pp. 1741-1785 ◽  
Author(s):  
RAIMUND BÜRGER ◽  
ANTONIO GARCIA ◽  
MATTHIAS KUNIK
Keyword(s):  
Particle Size ◽  
Kinetic Theory ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Density Function ◽  
Volume Fraction ◽  
Kinematic Model ◽  
Phase Density ◽  
Continuous Particle ◽  
Generalized Kinetic Model

Polydisperse suspensions with particles of a finite number N of size classes have been widely studied in laboratory experiments. However, in most real-world applications the particle sizes are distributed continuously. In this paper, a well-studied one-dimensional kinematic model for batch sedimentation of polydisperse suspensions of small equal-density spheres is extended to suspensions with a continuous particle size distribution. For this purpose, the phase density function Φ = Φ(t, x, ξ), where ξ ∈ [0, 1] is the normalized squared size of the particles, is introduced, whose integral with respect to ξ on an interval [ξ1, ξ2] is equivalent to the volume fraction at (t, x) occupied by particles of that size range. Combining the Masliyah–Lockett–Bassoon (MLB) model for the solid-fluid relative velocity for each solids species with the concept of phase density function yields a scalar, first-order equation for Φ, namely the equation of the generalized kinetic theory. Three numerical schemes for the solution of this equation are introduced, and a numerical example and an L1 error study show that one of these schemes introduces less numerical diffusion and less spurious oscillations near discontinuities than the others. Several numerical examples illustrate the simulated behavior of this kind of suspensions. Numerical results also illustrate the solution of an eigenvalue problem associated with the equation of the generalized kinetic theory.

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