Modeling of the Mechanical Properties of a Polymer-Metal Foam Interpenetrating Phase Composite

Abstract

An interpenetrating phase composite is made by injection molding thermoplastic polymers into the voids of open-cell aluminum foam. Two types of polypropylene and an acetyl were mechanically introduced into the open cells of a Duocel® aluminum foam. Prior experimental work revealed that the combination of the polymer and the metal foam yields a hybrid that is stiffer than the polymer alone but has a reduced tensile strength. A finite element model using a tetrakaidecahedral unit cell is used to model the metal foam ligaments with the polymer occupying the remaining space. The geometric model as well as the interface between the two materials were validated against the experimental results. The resulting conclusions are that the aluminum ligaments oriented along the load direction cause an increase in stiffness but ligaments oriented laterally cause stress concentration that yield lower strength. The finite element model is used to give both qualitative and quantitative explanations of the physics of the interrelations between the metal foam and the polymer.