Multiscale homogenization method for the prediction of elastic properties of fiber-reinforced composites

2020 ◽  
Vol 203 ◽  
pp. 249-263 ◽  
Author(s):  
Wenya Shu ◽  
Ilinca Stanciulescu
2019 ◽  
Vol 54 (8) ◽  
pp. 1031-1048 ◽  
Author(s):  
Yang Yang ◽  
Qi He ◽  
Hong-Liang Dai ◽  
Jian Pang ◽  
Liang Yang ◽  
...  

A micromechanical model for short fiber-reinforced composites (SFRCs) with functionally graded interphases and a systematic prediction scheme to determine the effective properties are presented. The matrix and the fibers are regarded to be linear elastic, isotropic, and homogeneous. Fibers are assumed to be ellipsoids coated perfectly by functionally graded interphases, which is supposed to be formed chemically or physically by the constituents near the interface. First, to analyze the grading interphase effect, layer-wise concept is followed to divide the functionally graded interphases into multi-homogeneous sub-layers. Next, to take the effect of functionally graded interphases into account, a combination of multi-inclusion method and Mori–Tanaka method is applied to predict effective elastic properties of this unidirectional SFRCs with respect to the content and aspect ratio of the inclusions. By employing coordinate transformation, spatially elastic moduli are obtained. Finally, Voigt homogenization scheme is used to obtain the overall, averaged, symmetrical elastic properties of the SFRCs. Numerical examples and analyses demonstrate the applicability of the proposed method and indicate the influences of graded interphase, orientation, and aspect ratio of inclusions as well as properties and contents of the constituents on the overall properties of SFRCs.


Author(s):  
Xiaochun Wang

There are many methods on computation of transverse elastic properties of unidirectional fiber-reinforced composites when using the finite element method, such as three-dimension model, two-dimension plane strain model, unit cell model, etc[1]. But unit cell models could be used only when the fibers are arrayed regularly. The computations of three- and two-dimension plane strain models are tremendous when many fine fibers are spread randomly in the matrix so that the properties of block of composite must be computed. The paper proposes a new embedded-zone method to compute the transverse elastic properties for a block of fiber-reinforced composites containing a great amount of fibers embedded in the matrix stochastically while using very little computational work compared with three- and two-dimension plane strain model. The transverse elastic modulus and shear modulus of unidirectional fiber-reinforced composites are computed.


Author(s):  
Yana Morenko ◽  
Pavlo Krokhmal ◽  
Olesya I. Zhupanska

This study is concerned with development of bounds on the elastic properties of fiber reinforced composites with arbitrary orientational distribution of fibers. Generalization of the Mori-Tanaka model [1] and Hashin-Schtrikman variational bounds [2] to the cases of non-aligned composite phases are examined. Orientation distribution functions (ODF) are used to describe orientation probability density. It is shown that the Mori-Tanaka scheme applied to the non-aligned fiber reinforced composites violates symmetry of the effective elastic moduli tensor. The study of the literature also reveals that there are no known bounds derived for the composites with orientational distribution (except for the random uniform distribution) of phases. To overcome this issue we propose to formulate a problem of finding tightest bounds for the composites with non-aligned phases as a nonlinear semidefinite optimization problem, i.e., an optimization problem where the optimization variables are represented by symmetric positive semidefinite matrices. Such a formulation guarantees that any solution of the optimization problem represents a valid tensor of elastic material properties. The optimization problem then is solved by an interior point method to produce optimal bounds for the overall elastic properties of two-phase composite with uniform distribution of carbon nanotubes in a polymer matrix.


Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 722 ◽  
Author(s):  
S. Z. H. Shah ◽  
Puteri S. M. Megat Yusoff ◽  
Saravanan Karuppanan ◽  
Zubair Sajid

This paper presents a multi-scale-homogenization based on a two-step methodology (micro-meso and meso-macro homogenization) to predict the elastic constants of 3D fiber-reinforced composites (FRC). At each level, the elastic constants were predicted through both analytical and numerical methods to ascertain the accuracy of predicted elastic constants. The predicted elastic constants were compared with experimental data. Both methods predicted the in-plane elastic constants “ E x ” and “ E y ” with good accuracy; however, the analytical method under predicts the shear modulus “ G x y ”. The elastic constants predicted through a multiscale homogenization approach can be used to predict the behavior of 3D-FRC under different loading conditions at the macro-level.


2019 ◽  
Vol 286 ◽  
pp. 03004
Author(s):  
L. Lakhal ◽  
Y. Brunet ◽  
T. Kanit

The aim of this work is to efficiently select samples of non-overlapping parallel fiber reinforced composites with regard to their elasticity and their fiber distribution in the composite cross-section. The samples were built with the help of the simulated annealing technique according to chosen Radial Distribution Functions. For each sample the fields of local stresses were simulated by finite element method, then homogenized by volume averaging in order to investigate their elastic properties. The effect of RDF shape on elastic properties was quantified. The more the fiber distributions deviate from Poisson’s Law the higher the effective elastic moduli are. A method to select samples of real fiber reinforced composites according to their elasticity is proposed.


Sign in / Sign up

Export Citation Format

Share Document