Hierarchical homogenization and experimental evaluation of functionally graded materials manufactured by the fused filament fabrication process

This research study investigates the numerical and experimental characterization of Functionally Graded Materials (FGMs) fabricated by the fused filament fabrication (FFF) process. To design and fabricate FGMs, the gradient-based digital structures were designed using the voxelization method and manufactured with flat and on edge printing orientations. The direct and gradual transition patterns were fabricated, and tensile test method was used to characterize the interface strength. The results indicated that the gradual change in fiber reinforcement reduced the stress concentrations at the interface zone and increased the strength of neat Acrylonitrile Butadiene Styrene (ABS) properties. The homogenization approach was applied along with the finite element method to predict the effective material properties of FFF-made FGMs. It was found that the homogenized values were close to the experimental test results with around 5 % error for flat-oriented parts. Overall, this research work presents an important step toward enabling the effective design and analysis of composite structures using an experimental characterization and computational methodology.