A novel method for tailoring elasticity distributions of functionally graded porous materials

As foams having hierarchical mechanical properties, functionally graded porous materials (FGPMs) can satisfy multifold functional constraints whilst minimizing weight. In this paper, a novel method is proposed for goal driven design and fabrication of open-cell FGPMs with tailored elasticity distributions. To achieve the continuity in both structural geometry and mechanical properties, irregularly smooth porous structures, which have naturally realistic appearance, are designed by combining 3D Voronoi diagrams and skeleton-based implicit surfaces. A procedural modeling method integrating additive manufacturing (AM) is developed for avoiding the FGPM full representations which consume tremendous computational memory. For easily mapping the graded porous structures to yield tailored elasticity distributions, a mapping model from the elasticity distribution to the density field is formulated. The method is experimentally and numerically validated. Additionally, the compression tests showed the superior mechanical performance compared to straight-beam-based foams, and the stiffness and strength of the foam are found to be improved as a result of FGPMs. This research opens up a new route of tailoring the novel foams.