Fatigue Behaviour of Additively Manufactured Short Fibre Reinforced Polyamide

Additive manufacturing of Short Fibre Reinforced Polymers (SFRPs) combines good mechanical properties with high design flexibility. In this work, fatigue tests were performed on SFRP specimens with 0◦/90◦ and ±45◦ raster orientations. Thermal and mechanical fatigue regimes were both observed. In thermal fatigue, self-heating, softening and changes in viscoelastic properties occurred. In mechanical fatigue, the material progressively stiffened, and dissipative effects due to viscoelasticity were reduced. Such a behaviour is unusual for composites, but mainly seen in neat polymers. These results suggest the fatigue behaviour of this material to be dominated by the polyamide matrix.