Experimental and numerical investigation into axial compressive behaviour of thin-walled structures filled with foams and composite skeleton

This study investigated crashworthiness characteristics of a circular aluminum tube internally reinforced with a composite skeleton and aluminum foams subjected to quasi-static axial crushing load. For a comparative purpose, an empty tube and tubes with single reinforcement (aluminum foams or composite skeleton) were tested as well. The deformation patterns and several key parameters related to the crashworthiness of these structures were investigated and compared. The experimental results showed that the proposed design offered the best energy absorption characteristics, and the specific energy absorption increased by 32% compared to the empty tube. In order to explore the mechanisms of enhancement in energy absorption, the composite skeleton and the tube filled with separated foams were tested, and the strong interaction between foams and the skeleton has been found to have a very remarkable contribution to total energy absorption. Additionally, numerical models were built based on different material constitutive relationships and validated by experimental results. Further parametric studies were performed to investigate the effects of tube thickness, skeleton thickness and foam density on crashworthiness. It is found that tube thickness is more important to affecting crashworthiness, which provides a basis for structural optimization.