The effect of percent foam fill ratio on the energy absorption capacity of axially compressed thin-walled multi-cell square and circular tubes

In this study, the effect of foam fill ratio on the energy absorption capacity of axially compressed thin-walled multi-cell square and circular tubes is investigated. In the experimental study, Aluminum tubes having circular cross-sections with four different foam fill ratio (11.4%, 22.8%, 34.2%, 100%) were subjected to compression tests under quasi-static test conditions. The finite element (FE) models of these tests were prepared and FE analysis were conducted using LS-DYNA program for validation study. After validating the FE models with real experiments, a total of 24 different multi-cell geometries (6 square empty, 6 square with various foam fill ratio, 6 circular empty and 6 circular with various foam fill ratio) were created. A total of three different wall thicknesses were used for each geometry in the explicit dynamic analyses. It is found out that specific energy absorption (SEA) of foam-filled square design is 5 times larger compared to the empty square design which has minimum SEA. By varying the wall thickness, the SEA and crush force efficiency (CFE) performances of the foam-filled square design can be increased by 87% and 42% respectively. The main goal of this study is to find the best multi-cell design having maximum SEA and CFE.