Fatigue behaviour and rate-dependent properties of aramid fibre/carbon fibre hybrid composites

This work presents preliminary investigations of the fatigue behaviour of hybrid composite materials in flexure by three methods; examination of the hybrid effects of S-N data as a function of the fibre types and structure of the material; study of the rate-dependent flexural behaviour and its correlation with the fatigue life; and by incremental loading tests to simulate fatigue. Aramid fibre/carbon fibre hybrids with aramid skin and carbon core exhibited a positive hybrid effect on flexural strength. Their properties were superior to those with carbon fibre skin and aramid fibre core. A possible explanation for the positive effect in the ACA hybrids may lie in the strain rate dependence of these materials. The reasons for the high strain rate dependence are discussed.