Sensitivity to notch effect of additively manufactured polymers and polymer-matrix composites

The notch effect, defined as the increase in the material fracture resistance when the defect that causes the final fracture has a finite (non-negligible) radius on the tip, may be of great importance from a structural integrity point of view. Thus, when containing defects, materials with a large notch effect develop a considerable increase in their load bearing capacity as the radius at the defect tip increases. On the other hand, Fused Filament Fabrication (FFF) is a growing technology which, in the case of polymers and polymer-matrix composites, has found (so far) its greatest application in the manufacturing of prototypes. In order to develop FFF polymeric and polymer-matrix composites with engineering applications, such as structural components, it is necessary to have a sound knowledge of their mechanical behavior in the presence of defects. In this work, the fracture behavior of some commonly used FFF polymers and composites (ABS, PLA, PLA-Gr, ASA and ASA-CF), is analyzed. The analysis is performed in both cracked and notched conditions, quantifying their sensitivity to the notch effect.