Study on low-velocity impact response and residual strength of ultralight all-CFRP sandwich structure

The all-CFRP sandwich structure with ultralight honeycomb is designed and manufactured by stretching process. Two scenarios, including global and local impact, are considered to reveal the characteristics of impact resistance. The effects of different impact energies and core densities on energy absorption and failure mechanism are thoroughly discussed. Meanwhile, the post-impact residual compressive strength is carried out to evaluate the influence of impact on structural strength and stability. The results show that under the global impact, the impact resistance is related to core density, and the energy absorption is mainly from honeycomb core. While under the local impact, as the impact energy increases, the failure mechanism of the structure changes from core crushing to penetration. The research provides a guidance for low-velocity impact performance and structural optimization design of sandwich structures.