Compression and hydrothermal ageing after impact of carbon fibre reinforced epoxy laminates

Abstract

This paper proposes a new methodology for the assessment of seawater ageing effects on impact-damaged composite laminates. CF/Epoxy laminates which were unimpacted, and impacted at 30 J, 60 J, and 90 J by hemispherical and conical impactors were subject to 4 months hydrothermal ageing in renewed natural seawater at 60 +/-2 °C. The majority of water uptake by impacted laminates (0.05 wt% − 0.3 wt%) occurred in the first 24 h and is believed to be held in damage cavities by capillary mechanisms. The increase in diffusive water uptake rate by the matrix due to impact damage was only small, at less than 0.008 wt%.mm.hr−0,5, compared with the total diffusive water uptake rate of 0.1 wt%.mm.hr−0,5. Hydrothermal ageing reduced the residual compressive strength of pristine laminates by 25 % and impact-damaged laminates by 8 % to 16 % for impacts between 30 J and 90 J.