Micromechanical Approach of the Coated Inclusion Problem and Applications to Composite Materials

1994 ◽  
Vol 116 (3) ◽  
pp. 274-278 ◽  
Author(s):  
M. Cherkaoui ◽  
H. Sabar ◽  
M. Berveiller
Keyword(s):  
Hollow Spheres ◽  
Micromechanical Model ◽  
Inclusion Problem ◽  
Micromechanical Approach ◽  
Self Consistent ◽  
Polyester Matrix ◽  
Coated Inclusion ◽  
Homogeneous Matrix ◽  
Theoretical Results ◽  
Good Agreement

A micromechanical model using simultaneously Green’s function techniques and interfacial operators is proposed in order to solve the elastic inhomogeneous coated inclusion problem. For a composite material made of a non dilute concentration of coated inclusions and a homogeneous matrix, the interactions between the reinforcements are solved by a self-consistent scheme. The theoretical results for a composite of hollow spheres of glass in a polyester matrix are in good agreement with experimental measurements of Huang and Gibson.

Micromechanical Model Prediction Overall Young Modulus Nanocomposites Polymer-Clay-Silica by Self Consistent Approach

2014 ◽  
Vol 980 ◽  
pp. 152-156
Author(s):  
Amar Mesbah ◽  
Krimo Azouaoui ◽  
Sid Ali Kaoua ◽  
Salah Boutaleb
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Elastic Constants ◽  
Model Prediction ◽  
Micromechanical Model ◽  
Young Modulus ◽  
Polyamide 6 ◽  
Micromechanical Approach ◽  
Self Consistent ◽  
Consistent Approach

In order to address the problem of stiffness and mechanical properties, a micromechanical approach for the prediction of the overall modulus of nanocomposites (Nylon-6/nanoclay/silica) using a self-consistent scheme based on the double-inclusion model and taking into account the different morphologies exfoliated or intercalated of the nanoparticles. Self-consistent approach that is used in our calculations was explained after reviewing the inclusion of Eshelby, in particular the double inclusion and while considering also the effect of constrained region, modeled as an interphase around reinforcements. Namely, polyamide 6 reinforced with clay platelets and silica particles. Several parameters on the Young's modulus of the composite were studied to see the effect of having mixed two or three reinforcements in polymer matrix. Finally, we demonstrated the process undertaken for the calculation of elastic constants of the material studied.

A Micromechanical Model of the Tensile Behavior of Woven Fabric

1997 ◽  
Vol 67 (6) ◽  
pp. 445-459 ◽  
Author(s):  
M. L. Realff ◽  
M. C. Boyce ◽  
S. Backer
Keyword(s):  
Micromechanical Model ◽  
Tensile Behavior ◽  
Woven Fabric ◽  
Uniaxial Tensile ◽  
Stress Strain ◽  
Strain Behavior ◽  
Yarn Properties ◽  
Micromechanical Approach ◽  
Uniaxial Tensile Stress ◽  
Good Agreement

This work takes a micromechanical approach to fabric tensile modeling. The entire uniaxial tensile stress-strain behavior of the fabric is modeled from the constitutive yarn properties (tensile, bending, flattening, and consolidation behavior) and the original fabric geometry. Techniques for measuring these yarn properties are described. In most cases, there is good agreement between the theoretical and experimental results for several fabrics of differing weave and yarn construction. Modified approaches are suggested for those cases where prediction of fabric stress-strain behavior deviates from the experimental data.

The pressure and entropy of a unitary Fermi gas with particle-hole fluctuation

2018 ◽  
Vol 32 (01) ◽  
pp. 1750364
Author(s):  
Hao Gong ◽  
Xiao-Xia Ruan ◽  
Hong-Shi Zong
Keyword(s):  
Experimental Data ◽  
Fermi Gas ◽  
Experimental Measurements ◽  
Matrix Approximation ◽  
Self Consistent ◽  
Unitary Fermi Gas ◽  
T Matrix ◽  
Theoretical Results ◽  
Previous Prediction ◽  
Good Agreement

We calculate the pressure and entropy of a unitary Fermi gas based on universal relations combined with our previous prediction of energy which was calculated within the framework of the non-self-consistent T-matrix approximation with particle-hole fluctuation. The resulting entropy and pressure are compared with the experimental data and the theoretical results without induced interaction. For entropy, we find good agreement between our results with particle-hole fluctuation and the experimental measurements reported by ENS group and MIT experiment. For pressure, our results suffer from a systematic upshift compared to MIT data.

Four Phase Model: A New Formulation to Predict the Effective Elastic Moduli of Composites

2006 ◽  
Vol 129 (2) ◽  
pp. 313-320 ◽  
Author(s):  
El H. Barhdadi ◽  
P. Lipinski ◽  
M. Cherkaoui
Keyword(s):  
Elastic Moduli ◽  
Homogeneous Medium ◽  
Phase Model ◽  
Spherical Inclusions ◽  
Micromechanical Approach ◽  
Matrix Layer ◽  
Homogeneous Matrix ◽  
The Green Function ◽  
New Formulation ◽  
Good Agreement

We consider a linearly elastic composite medium, which consists of a homogeneous matrix containing coated spherical inclusions. The composite is modeled by a four phase pattern consisting of inclusion, interphase, matrix layer, and equivalent homogeneous medium. The overall elastic moduli are obtained using a micromechanical approach based on the Green function techniques and the interfacial operators. The four phase model assumes that all constituents are elastic and perfectly bonded. The model is used to derive the effective elastic properties of representative volume element using classical averaging schemes assuming the isotropy of constituent. Finally, effect of the thickness and stiffness of interphase on the global behavior of real composite materials are examined. Comparisons with experimental results show a good agreement.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

Studies of local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) crystals

2021 ◽  
Vol 76 (4) ◽  
pp. 299-304
Author(s):  
Fu Chen ◽  
Jian-Rong Yang ◽  
Zi-Fa Zhou
Keyword(s):  
Crystal Field ◽  
Elongation Ratio ◽  
Paramagnetic Resonance ◽  
Local Structures ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Theoretical Results ◽  
Good Agreement

Abstract The electron paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = x, y, z) and local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) are theoretically investigated using the high order perturbation formulas of these EPR parameters for a 3d 9 ion under orthorhombically elongated octahedra. In the calculations, contribution to these EPR parameters due to the admixture of d-orbitals in the ground state wave function of the Cu2+ ion are taken into account based on the cluster approach, and the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the studied EPR parameters with the local structures of the Cu2+ centers. Based on the calculations, the Cu–H2O bonds are found to suffer the axial elongation ratio δ of about 3 and 2.9% along the z-axis, meanwhile, the planar bond lengths may experience variation ratio τ (≈3.8 and 1%) along x- and y-axis for Cu2+ center in (NH4)2Zn(SO4)2·6H2O and Rb2Zn(SO4)2·6H2O, respectively. The theoretical results show good agreement with the observed values.

Isotope shift and hyperfine structure in the atomic spectrum of tin

1973 ◽  
Vol 332 (1588) ◽  
pp. 129-138 ◽  
Keyword(s):  
Stable Isotopes ◽  
Hyperfine Structure ◽  
Nuclear Charge ◽  
Light Sources ◽  
Atomic Spectrum ◽  
Nuclear Charge Distribution ◽  
Fabry Perot ◽  
Self Consistent ◽  
Structure Constants ◽  
Good Agreement

Three lines in the atomic spectrum of tin, λ 3262 Å, λ 3283 Å and λ 6454Å have been studied in emission under high resolution with the use of light sources containing enriched isotopic samples. Results are reported for isotope shifts in these lines for the abundant stable isotopes ( A ≽ 116). Pressure-scanned Fabry–Perot etalons provided the necessary resolution; the spectrograms for λ 6454 Å were recorded and analysed by digital techniques, and for this line hyperfine structure constants required in the interpretation of the data were also evaluated. The results for the three lines are not in good agreement with earlier work, but are shown to be self-consistent by means of a King plot. Their interpretation in terms of the nuclear charge distribution is considered in the following paper.

On the Flow Fields of Inertial Impactors

1974 ◽  
Vol 96 (4) ◽  
pp. 394-400 ◽  
Author(s):  
V. A. Marple ◽  
B. Y. H. Liu ◽  
K. T. Whitby
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Relaxation Method ◽  
Water Model ◽  
Navier Stokes ◽  
Visualization Technique ◽  
Navier Stokes Equations ◽  
Theoretical Results ◽  
Plate Distance ◽  
Good Agreement

The flow field in an inertial impactor was studied experimentally with a water model by means of a flow visualization technique. The influence of such parameters as Reynolds number and jet-to-plate distance on the flow field was determined. The Navier-Stokes equations describing the laminar flow field in the impactor were solved numerically by means of a finite difference relaxation method. The theoretical results were found to be in good agreement with the empirical observations made with the water model.

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

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