Effect of thermo-oxidative ageing on the thermo-mechanical responses of 3D braided carbon fiber/epoxy composites during high-speed impact

Abstract

By developing a thermo-mechanical coupled model, we quantitatively analyzed the effect of thermo-oxidative ageing on the temperature, thermal strain and thermal stress histories of braided composites during high-speed impact. We also considered temperature dependence of elastic modulus during impact in this model. The proposed model was first applied to the unaged composites, then the results were compared to the impact responses captured by the split Hopkinson bar and the high-speed camera. The comparisons of the experimental and numerical results show that the proposed model could capture the adiabatic temperature rise, stress-strain responses and failure process of braided composites during high-speed impact. The validated model was subsequently employed to thermo-oxidative aged composites. Results show that the temperature rise, thermal strain and thermal stress all depend on the mechanical properties of resin, and they decreased with the increase of ageing temperature since the performance of resin is compromised by thermo-oxidation ageing. The change of resin performance after ageing leads to the change in the temperature rise during impact, so the stiffness of composites will decrease in varying degrees after ageing.

Keywords:

• Three-dimensional braided composites
• thermo-mechanical coupled
• thermo-oxidative ageing
• high-speed impact

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the Changjiang Scholars Program (No. 11572085), National Science Foundation of China (No. 51675095, No. 51805210) and Jiaxing Program of Science and Technology (No. 2019AD32005). Shengkai Liu received financial support for his visit to the University of Alberta by the China Scholarship Council (No. 201806630034).