The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

Functional polymer foams are considered as a promising field which could potentially produce foams with added value. Specifically, functionally graded foams are materials which are expected to provide better mechanical properties while preserving low density in comparison with regular foams. In this thesis, a preparation process of such foams is designed, examination of prepared structure and comparison of mechanical properties with regular foams is performed. The obtained results are discussed and further research in this field is proposed.