Equivalent inclusion approach and approximations for conductivity of isotropic matrix composites with sphere-like, platelet, and fibrous fillers

2018 ◽  
Vol 37 (14) ◽  
pp. 968-980
Author(s):  
Trung Kien Nguyen ◽  
Duc Chinh Pham ◽  
Quoc Hoang Do
Keyword(s):  
Experimental Data ◽  
Effective Medium ◽  
Matrix Composites ◽  
Conductivity Data ◽  
Isotropic Matrix ◽  
Equivalent Inclusion ◽  
Circular Fiber ◽  
Experimental Reference ◽  
Fibrous Fillers

The construction starts from certain typical effective medium approximations for conductivity of idealistic isotropic matrix composites with randomly oriented inclusions of perfect spherical, platelet, and circular fiber forms, which obey Hashin–Shtrikman bounds over all the ranges of volume proportions of the component materials. Equivalent inclusion approach is then developed to account for possible diversions, such as non-idealistic geometric forms of the inhomogeneities, imperfect matrix-inclusion contacts, filler dispersions, and when the particular values of the fillers’ properties are unspecified, using available numerical or experimental reference conductivity data for particular composites. Illustrating applications involving experimental data from the literature show the usefulness of the approach.

scholarly journals Equivalent-inclusion approach for the conductivity of isotropic matrix composites with anisotropic inclusions

2016 ◽  
Vol 38 (4) ◽  
pp. 239-248 ◽  
Author(s):  
Do Quoc Hoang ◽  
Pham Duc Chinh ◽  
Tran Anh Binh
Keyword(s):  
Finite Elements ◽  
Effective Conductivity ◽  
Spherical Inclusion ◽  
Effective Medium ◽  
Matrix Composites ◽  
Isotropic Matrix ◽  
Equivalent Inclusion

Many effective medium approximations for effective conductivity are elaborated for matrix composites made from isotropic continuous matrix and isotropic inclusions associated with simple shapes such as circles or spheres, ... In this paper, we focus specially on the effective conductivity of the isotropic composites containing the disorderly oriented anisotropic inclusions. We aim to replace those inhomogeneities by simple equivalent circular (spherical) isotropic inclusions with modified conductivities. Available simple approximations for the equivalent circular (spherical)-inclusion media then can be used to estimate the effective conductivity of the original composite. The equivalent-inclusion approach agrees well with numerical extended finite elements results.

scholarly journals The Classical Nature of Thermal Conduction in Nanofluids

2010 ◽  
Vol 132 (10) ◽  
Author(s):  
Jacob Eapen ◽  
Roberto Rusconi ◽  
Roberto Piazza ◽  
Sidney Yip
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Strong Evidence ◽  
Thermal Conduction ◽  
Base Fluid ◽  
Liquid Mixtures ◽  
Large Set ◽  
Conductivity Data ◽  
Homogeneous Systems ◽  
Thermal Conductivity Data

We show that a large set of nanofluid thermal conductivity data falls within the upper and lower Maxwell bounds for homogeneous systems. This indicates that the thermal conductivity of nanofluids is largely dependent on whether the nanoparticles stay dispersed in the base fluid, form large aggregates, or assume a percolating fractal configuration. The experimental data, which are strikingly analogous to those in most solid composites and liquid mixtures, provide strong evidence for the classical nature of thermal conduction in nanofluids.

Two-Ellipsoidal Inhomogeneities by the Equivalent Inclusion Method

1975 ◽  
Vol 42 (4) ◽  
pp. 847-852 ◽  
Author(s):  
Z. A. Moschovidis ◽  
T. Mura
Keyword(s):  
Computer Program ◽  
Strain Field ◽  
Applied Strain ◽  
Stress And Strain ◽  
Isotropic Matrix ◽  
Equivalent Inclusion Method ◽  
Inclusion Method ◽  
Equivalent Inclusion ◽  
The Matrix ◽  
Final Stress

The problem of two ellipsoidal inhomogeneities in an infinitely extended isotropic matrix is treated by the equivalent inclusion method. The matrix is subjected to an applied strain field in the form of a polynomial of degree M in the position coordinates xi. The final stress and strain states are calculated for two isotropic ellipsoidal inhomogeneities both in the interior and the exterior (in the matrix) by using a computer program developed. The method can be extended to more than two inhomogeneities.

scholarly journals Thermal and Rheological Characterisation of a Thermoset Matrix for Filament Winding Modelling

2004 ◽  
Vol 13 (1) ◽  
pp. 096369350401300
Author(s):  
L. Calabrese ◽  
A. Celona ◽  
A. Valenza
Keyword(s):  
Experimental Data ◽  
Process Condition ◽  
Theoretical Models ◽  
Filament Winding ◽  
Numerical Code ◽  
Process Conditions ◽  
Thermal Treatments ◽  
Matrix Composites ◽  
Reinforced Plastics ◽  
Filament Winding Process

Rheo-kinetic behaviour of an epoxy resin, coupled with an aliphatic polyamines hardener, used in fibre reinforced plastics, was analysed comparing experimental data to theoretical models. Then the modelling of technological filament winding process for thermoset matrix composites, developed through a numerical code realized with MATLAB, is reported. The model includes winding and curing phase decoupling the manufacturing process into sub-models. Four sub-models are used: fibre motion, thermal, kinetic and rheological model. Considerable differences are obtained in process condition, using several thermal treatments. The numerical modelling helps to detect the process conditions to optimise the filament winding process.

HYBRID EXPERIMENTAL AND NUMERICAL CHARACTERIZATION OF THE 3D RESPONSE OF WOVEN POLYMER MATRIX COMPOSITES

2021 ◽  
Author(s):  
JAVIER BUENROSTRO ◽  
HYONNY KIM ◽  
ROBERT K. GOLDBERG ◽  
TRENTON M. RICKS
Keyword(s):  
Experimental Data ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Verification And Validation ◽  
Matrix Composites ◽  
Experimental Stress ◽  
Stress Strain ◽  
Material Models ◽  
Plain Weave ◽  
Model Input

The need for advanced material models to simulate the deformation, damage, and failure of polymer matrix composites under impact conditions is becoming critical as these materials are gaining increased usage in the aerospace and automotive industries. The purpose of this work is to characterize carbon epoxy fabrics for composite material models that rely on a large number of input parameters to define their nonlinear and 3D response; e.g. elastic continuum damage mechanics models or plasticity damage models [1, 2]. It is challenging to obtain large sets of experimental stress-strain curves, therefore, careful selection of physical experiments that exhibit nonlinear behavior is done to significantly reduce the cost of generating threedimensional material databases. For this work, plain weave carbon fabrics with 3k and 12k tows are manufactured by VARTM. Testing is done using MTS hydraulic test frames and 2D digital image correlation (DIC) to obtain experimental stress-strain curves for in-plane tension and shear as well as transverse shear. For cases where actual experimental data is either not available or difficult to obtain, the required model input is virtually generated using the NASA Glenn developed Micromechanics Analysis Method/Generalized Method of Cells (MAC/GMC) code. A viscoplastic polymer model is calibrated and utilized to model the matrix constituent within a repeating unit cell (RUC) of a plain weave carbon fiber fabric. Verification and validation of this approach is done using MAT213, a tabulated orthotropic material model in the finite element code LS-DYNA, which relies on 12 input stress-strain curves in various coordinate directions [2]. Based on the model input generated by the micromechanics analyses in combination with available experimental data, a series of coupon level verification and validation analyses are carried out using the MAT 213 composite model.

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