# Investigation on Damage and Energy Absorption Performance of Aluminum Foam Sandwich Plates Under Low-Velocity Impact

## TL;DR

This study examines how aluminum foam sandwich plates behave under low-velocity impact, focusing on their deformation, failure, and energy absorption in marine structures.

## Contribution

The study provides new insights into the effects of impactor diameter and low-temperature environments on the penetration behavior of aluminum foam sandwich plates.

## Key findings

- The upper face sheet of AFSPs primarily exhibits shear failure, while the lower face sheet undergoes global bending and tensile fracture.
- Smaller impactors (25 mm) are more likely to penetrate the lower face sheet, reducing energy absorption compared to larger impactors.
- Energy absorption increases by about 8% at low temperatures (−60 °C) compared to normal temperature (20 °C).

## Abstract

Marine structures may suffer collision during navigation, leading to plastic deformation or even fracture failure of the structure, which poses a serious threat to ship structural safety. In this study, INSTRON 9350 Drop Tower was employed to carry out the impact test on the aluminum foam sandwich plates (AFSPs). The penetration performance of AFSPs were analyzed, including deformation mode, failure mode, impact force, displacement, energy absorption, and loading–unloading process. Additionally, the effects of impactor diameter and low-temperature environment on the penetration behavior of AFSPs were explored. The results indicate that the upper face sheet primarily exhibits shear failure, while the lower face sheet mainly undergoes global bending and tensile fracture. As the impact energy increases, the deformation zone of the lower face sheet extends to the boundary of the effective area of the sandwich plates. The loading stage of AFSPs under different impact energies generally coincide, but the unloading stage shows significant differences. Moreover, the peak impact force of the case D40 is nearly twice that of the case D25, while the 25 mm impactor is more likely to penetrate the lower face sheet, so that the energy absorption of the smaller impactor is reduced. Under penetration conditions, higher impact energies resulted in faster energy absorption rates, but the final absorbed energy values were almost identical. Ambient temperature affects the penetration performance of AFSPs; as the temperature decreases, the permanent deflection of the upper face sheet and the rebound velocity of the impactor decrease, whereas energy absorption increases. Compared with the normal temperature (20 °C), the energy absorption increases by about 8% at low temperature (−60 °C).