Three-dimensional numerical modelling of discontinuous fibre composite architectures

A three-dimensional geometrical model is presented for generating discontinuous random fibre architectures consisting of high filament count bundles. The fibre network model randomly distributes fibre bundles in a three-dimensional volume using a non-contact algorithm, together with Catmull–Rom spline interpolation, to provide a physically representative material. Only the spines of the fibre bundles are modelled, using truss elements to permit high fibre volume fractions of up to 60%, with no restriction on the fibre bundle aspect ratio. ABAQUS/Standard is used to predict the tensile performance for coupons with varying levels of out-of-plane fibre curvature. The effect of fibre curvature was found to be insignificant for tensile modulus, but a 34% reduction in ultimate tensile strength (UTS) was observed when adjusting the maximum permissible out-of-plane angle of fibres from 1 to 35°. A novel method for characterising the degree of out-of-plane fibre curvature within experimental test coupons is also discussed.