Composite Materials Research Progress

In: Composite Materials Research Progress ISBN: 1-60021-994-2
Editor: Lucas P. Durand, pp. 1-50 © 2008 Nova Science Publishers, Inc.
Chapter 1
MULTI-SCALE ANALYSIS OF FIBER-REINFORCED
COMPOSITE PARTS SUBMITTED
TO ENVIRONMENTAL AND MECHANICAL LOADS
Jacquemin Frédéric and Fréour Sylvain *
GeM -Institut de Recherche en Génie Civil et Mécanique, Université de Nantes-Ecole
Centrale de Nantes-CNRS UMR 6183, 37 Boulevard de l’Université, BP 406,
44 602 Saint-Nazaire, France
Abstract
The purpose of this work is to present various application of statistical scale transition
models to the analysis of polymer-matrix composites submitted to thermo-hygro-mechanical
loads. In order to achieve such a goal, two approaches, classically used in the field of
modelling heterogeneous material are studied: Eshelby-Kröner self-consistent model on the
one hand and Mori-Tanaka approximate, on the second hand. Both models manage to handle
the question of the homogenization of the microscopic properties of the constituents (matrix
and reinforcements) in order to express the effective macroscopic coefficients of moisture
expansion, coefficients of thermal expansion and elastic stiffness of a uni-directionally
reinforced single ply. Inversion scale transition relations are provided also, in order to identify
the effective unknown behaviour of a constituent. The proposed method entails to inverse
scale transition models usually employed in order to predict the homogenised macroscopic
elastic/hygroscopic/thermal properties of the composite ply from those of the constituents.
The identification procedure involves the coupling of the inverse scale transition models to
macroscopic input data obtained through either experiments or in the already published
literature. Applications of the proposed approach to practical cases are provided: in particular,
a very satisfactory agreement between the fitted elastic constants and the corresponding
properties expected in practice for the reinforcing fiber of typical composite plies is achieved.
Another part of this work is devoted to the extensive analysis of macroscopic mechanical
states concentration within the constituents of the plies of a composite structure submitted to
thermo-hygro-elastic loads. Both numerical and a fully explicit version of Eshelby-Kröner
model are detailed. The two approaches are applied in the viewpoint of predicting the
mechanical states in both the fiber and the matrix of composites structures submitted to a
* E-mail address: sylvain.freour@univ-nantes.fr. Fax number : +33240172618. (Corresponding author)