Impact Strength for 3D-Printed PA6 Polymer Composites under Temperature Changes

This paper shows how temperature influences impact energy for continuous fiber additively manufactured (AM) polymer matrix composites. AM composites were fabricated with a nylon-based matrix and four continuous reinforcements: fiberglass, high-temperature fiberglass (HSHT), Kevlar, and carbon. The tested temperatures ranged from −40 to 90 °C. The chosen printed configuration for the lattice structure and fiber volume was the configuration that was found to perform the best in the literature, with a volumetric fiber content of 24.2%. Impact tests showed that the best response was fiberglass, HSHT, Kevlar, and carbon, in that order. The impact resistance was lowered at temperatures below ambient temperatures and above 50 °C. Additionally, each material’s impact energy was adjusted to third-degree polynomials to model results, with correlation factors above 92%. Finally, the failure analysis showed the damage mechanisms of matrix cracking, delamination in the printing direction, fiber tearing, and fiber pulling as failure mechanisms.