Elastic anisotropy of a transversely isotropic random network of interconnected fibres: non-triangulated network model

Solid networks made by inducing interconnection at fibre contact points in an assembly of fibres usually present a high elastic anisotropy. The paper aims at elucidating the dependence of the stiffness matrix of a random planar fibre network on fibre volume fraction V-f and out-of-plane fibre orientation psi. A periodic model is designed for representing the network architecture. Bounds for the elastic constants are obtained by calculating volume weighted averages of the elastic properties for periodic networks characterised by a uniform distribution of in-plane fibre orientations. Predictions are derived for the dependence of the in-plane Young's modulus, out-of-plane Young's modulus, and in-plane shear modulus on V-f and psi. The model is assessed by reference to experimental results for a network of metallic fibres. The underestimation of experimental results is presumed to be due to the fact that the model does not account for the effect of triangulation. (C) 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.