Foams are low density solids widely used as cushioning structures, due to their ability to undergo large amounts of plastic crushing at fairly constant stress levels. Since the mid-1980s, interest in functionally graded materials (FGMs) has grown steadily. FGMs are typically composed of two base materials (traditionally metal and ceramic) in which the composition of the FGM varies spatially and gradually from one base material to the other. More recently, functionally graded foam materials (FGFMs) have become a popular topic of research. FGFMs differ from FGMs in that they vary in density...