Parametric study of the tensile behaviour of unidirectional hybrid carbon/glass composites

The hybrid effect, which is the apparent failure strain enhancement of brittle fibres in a hybrid composite, was analysed for unidirectional carbon/glass hybrid composites. The hybrid effect strongly depended on the hybrid volume fraction and was found to be up to 36%. This was explained based on a reduction of the number of pathways for break cluster growth, and a delay in break cluster development to larger strains. The critical cluster size of hybrid composites also positively deviates from the linear rule-of-mixtures, contributing to the hybrid effect. Similarly, increased fibre dispersion decreased the number of pathways for break cluster growth, delayed break cluster development and increased the hybrid effect. The critical break cluster size was not affected by the dispersion. These results provide new insight into the failure development of hybrid composites and can help in their further optimisation.