The effects of creep and fatigue stress ratio on the long-term behaviour of angle-ply CFRP

The long-term behaviour of ±45°-angle-ply laminates of carbon/epoxy was studied. Due to the absence of 0°-layers angle-ply laminates are subject to cyclic creep. The creep strain evolution was investigated by experimental and analytical means. To predict the total strain depending on the applied stress level and load time an empirical creep law based on power law functions was adopted. Good agreement between experiment and prediction was found. The interaction between creep and fatigue was used to estimate a lower bound of the endurance limit based on creep predictions exclusively.