A model for the consolidation of hexagonal array matrix coated fibre composites

Abstract

Physically based constitutive equations for the consolidation of matrix coated fibres (MCFs) arranged in hexagonal arrays are presented in this paper. The constitutive equations have firstly been developed using a variational method for a unit cell representing hexagonal array packing of the coated fibres under symmetric in-plane compressive load. The resulting constitutive equations have subsequently been generalized to multiaxial stress states and implemented into finite element software within a finite deformation framework to enable simulations of practical manufacturing processes. The model has been validated by comparing predicted results with those obtained from independently developed explicit micromechanical finite element models. The ability of the model to predict the observed behaviour has been tested by comparing the results of simulations with those of experiments. The model predictions compare well with the measured results. In addition the results of simulations suggest that the densification curves for square and hexagonal array packing effectively provide the lower and upper bounds, respectively, for practical consolidation behaviour of MCFs under uniaxial constrained compression.