On the post-impact fatigue behavior and theoretical life prediction of CF/ PEEK-titanium hybrid laminates using an energy dissipation approach

This paper aims to illustrate the effect of the impact damage on fatigue behavior of CF/PEEK-titanium hybrid laminates. To achieve this end, a fatigue life model was proposed to predict the S-N curves of the laminates at various initial impact energy levels and stress ratios based on the energy dissipation approach. The energy dissipation behavior of the laminates during fatigue loading under different experimental conditions was analyzed through a large amount of post-impact fatigue tests, and the correlation between the initial impact damage and the total fatigue dissipation energy was determined. The full-field axial strain distribution of the titanium layer on the impacted side of the laminate was characterized in terms of initial impact energy level and maximum stress using digital image correlation, and then the post-impact fatigue failure mechanism of CF/PEEKTi hybrid laminates was summarized. Finally, the validity of the proposed model was verified by fatigue tests under other conditions of stress ratio and impact energy level. It is worth mentioning that the proposed model is also applicable to other types of FMLs, and can accurately predict the residual fatigue life of laminates after impact with only one set of S-N curve data.

Automated summary

This paper investigates the effect of impact damage on the fatigue behavior of CF/PEEK-titanium hybrid laminates. A fatigue life model is proposed to predict the S-N curves of the laminates based on energy dissipation approach. The energy dissipation behavior of the laminates under different experimental conditions is analyzed through post-impact fatigue tests, and the correlation between impact damage and fatigue dissipation energy is determined. The validity of the proposed model is verified through fatigue tests under different stress ratios and impact energy levels.