Quantifying fatigue property changes in material jetted parts due to functionally graded material interface design

The capability of Additive Manufacturing (AM) to manufacture multi-materials allows the fabrication of complex and multifunctional objects with heterogeneous material compositions and varying mechanical properties. The material jetting AM process specifically has the capability to manufacture multi-material structures with both rigid and flexible material properties. Existing research has investigated the fatigue properties of 3D printed multi-material specimens and shows that there is a weakness at multi-material interfaces. This paper seeks to, instead, investigate the effects of gradual material transitions on the fatigue life of 3D printed multi-material specimens. In order to examine the fatigue life at the multi-material interface, stepwise gradients are compared against continuous gradients created through voxel-based design. Results demonstrate the effects of different material gradient patterns and different material transition lengths on the fatigue life of multi-material specimens. In addition, the behavior of individual material composites is studied to confirm how gradient designs based on different material compositions affect their material properties.