Nonlinear finite element analysis of the crush behaviour of functionally graded foam-filled columns

The use of metallic foams as a filler in thin-walled structures can significantly enhance their crashworthiness characteristics. It is further believed that tailoring the properties of the foam filler would enhance the energy absorption characteristics of the foam-filled structure. It is the objective of this study to examine the crush behaviour of density-graded foam-filled columns and evaluate the effect of the density distribution upon both total and specific energy levels. The effect of density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. To this end, nonlinear parametric finite element simulations were developed and performed to achieve this objective. The results show relative improvement of 12% in specific energy absorption levels of density-graded foam-filled structures over their uniform density counterparts with the same mass.