Determination of the Size of Representative Volume Elements for Discontinuous Fibre Composites

Discontinuous fibre composites can be rapidly manufactured using automated processes, with low production costs compared with textile reinforcements [1]. The level of flexibility offered by discontinuous fibre composites can however make efficient design challenging, as additional material and process parameters complicate material selection and quality can be difficult to control compared with textiles. Part consistency can be poor and local material variability can be high [2, 3] if the wrong material parameters are chosen, leading to over conservative safety factors. Predictive models are considered to be important for reducing the level of costly experimental testing during screening and to drive future process and material developments. Developments in high performance computing have seen an increase in the use of numerical techniques such as Finite Element Analysis (FEA), to model the response of randomly distributed fibre composites. This approach is well documented for studying the transverse response of randomly distributed filaments [4, 5] or spherical inclusions [6] at the micro-scale, but is not so common for modelling 3D randomly packed fibres at the meso-scale. These architectures are far more challenging to model with many more independent variables to consider, particularly for high fibre volume fractions and large aspect ratio fibres [7]. This paper presents a novel method for meshing discontinuous fibre architectures for FEA, which removes many of the limitations imposed by conventional approaches. A random adsorption model has been used to generate architectures in order to study the influence of two different boundary condition strategies on a range of cells containing randomly distributed fibres. 2 RVE Generation for Random Fibre.