Effect of combined gradation in cross-sectional area and density on the dynamic compressive behavior of foams for moderate impact velocities

The effect of combined gradation in area and density on the dynamic response of foams is studied in this work. The cross-sectional area and density are graded such that the product of these quantities results in a tri-linear variation along the foam's length, and hence, the foam type is designated as Type-TL. A theoretical model based on the R-PP-L idealization is developed to study the response of the Type-TL foam struck by a rigid projectile. The Type-TL foam offers force distribution over a considerably larger area than a homogeneous foam, which may benefit structural protection.