*WINNER* Experimental and numerical characterization of functionally graded materials fabricated by the fused filament fabrication process

Abstract

In this research study, mechanical and numerical characterization of functionally graded materials (FGM) fabricated by the multi-material fused filament fabrication (FFF) process have been studied. Design and digital fabrication of tensile, flexural, and compression samples have been performed using the voxelization method. Test samples were mechanically tested, and the results showed that the strength and modulus of ABS material enhanced significantly with the addition of PC material into the ABS matrix. Since the interface of multi-material parts is crucial and needs substantial improvement, different interface patterns were designed and mechanically tested using the tensile test method. Tensile strength of gradient pattern yielded better results than other joint types such as interlock and direct interface. Analysis of variance was also applied to understand the process-property-structure relationships. Microstructural samples showed that there are periodic voids between adjacent beads and layers of FFF-made parts. Therefore, a numerical homogenization method has been applied to obtain a mesoscale material property using Ansys Material Designer before performing macroscale finite element implementation. The results of numerical methods showed less than 10% error with respect to the experimental test results. Overall, the FFF process with FGM could have potential applications in medical, structural, and automotive industries by locally varying material properties. This study presents a unique method of fabricating FGM structures with a low-cost manufacturing process.