Energy absorption of bio-inspired multi-layered graded foam-filled structures under axial crushing

Abstract

In this paper, an innovative bio-inspired multi-layered graded foam-filled structure (MGFS) mimicking the characteristics of the human skeleton was proposed in an attempt to improve the energy absorption. The proposed structures consisted of three layers of aluminum foam with different densities filled in three concentric aluminum circular tubes. To find out the optimal foam-filled combination and demonstrate the superior energy absorption performance of the proposed structures, a series of quasi-static compression tests were experimentally and numerically carried out. The results showed the proposed structures had higher energy absorption efficiency than that of both uniform foam-filled structures and the empty tubes, and Model-1 with the foam density increasing from the inner tube to the outer tube was the best combination mode. Furthermore, parametric numerical studies on Model-1 revealed that the diameter and thickness of the aluminum tube and the density of the aluminum foam had significant effects on the energy absorption characteristics. Finally, a theoretical model was developed to predict the mean crushing force of the bioinspired MGFS, which was in good agreement with the experimental results. This study provides an effective guideline for designing a foam-filled energy absorber with high energy absorption efficiency.