Numerical Evaluation on Impact Behavior of Functionally Graded Foam Materials

In order to use functionally graded foam materials (FGFM) effectively as an impact absorbing material, the impact behavior of FGFM which have density distribution in compressional direction was investigated with finite element analysis. FGFM was assumed to be laminated structure consisting of several homogeneous foams with different densities. The compressive stress-strain relations depending on the densities in FGFM were linearly approximated in three distinct deformation regions: elastic region, plateau stress region and densification region. Theoretical analysis of the static compression and finite element analysis on the dynamic compression were performed for the FGFM. The results of finite element analysis revealed that FGFM having high density in near the impact end can absorb a large amount of impact energy without increasing the maximum fixed end load from that of the homogeneous foam.