Influence of the architecture on the strength of a unidirectional composite with recycled discontinuous fibres

Abstract

Recycled fibre composites are made of discontinuous fibres that are not of the same length. Their mechanical behaviour depends on the load transfer between fibres and in particular on the overlaps between fibres of different lengths. The objective of the study is to show the influence of the architecture on the failure of a discontinuous reinforcement composite. A numerical model was developed to simulate different overlap lengths between fibres. The influence of defects, in this study small overlap length between fibres, and of their distribution in the architecture, was thus highlighted. Experimental tests allowed to validate the model. The model makes it possible to calculate a critical overlap length, length from which the composite strength reaches its maximum. In particular, simulations showed that discontinuous fibre architectures with small overlap lengths at the edge strongly decrease the strength of the composite. On the contrary, defects in the core of the architecture are tolerable. These results open perspectives for the choice of architectures based on recycled fibre in order to optimize the final properties of the composite.