Weight-saving potential of open-and closed-cell functionally graded foams under compressive loading

The weight-saving potential of open-and closed-cell functionally graded foams in structural applications is studied. Optimisation of material microstructures can lead to the design of lightweight foams that can effectively withstand applied loads and mitigate damage. A tetrakaidecahedron-shaped cell, which packs to fill space in three dimensions, is used to create open-and closed-cell foam models. Four functionally graded models and a plain foam model, all containing three vertically stacked cells, are studied for both open-and closed-cell foams. A density gradient is applied along the axial direction of the structures. The relative stiffness per unit mass for the closed-cell foams is found to be several orders of magnitude higher compared with that of the open-cell foams. The relative stiffness per unit mass is observed to change more rapidly for the open-cell foams than the closed-cell foams as the gradient decreases. This indicates retention of specific stiffness for closed-cell foams over a wide spectrum of density gradients. This study demonstrates the weight-saving potential of functionally graded foams in designing damage-tolerant structures and helps in optimising the geometrical parameters of foams for obtaining the desired set of properties.