Evaluation of the mechanical properties of 3D printed Nylon 11-continuous stainless steel fibre reinforced composites

This paper reports for the first time, on the 3D printing of Nylon 11 (PA11) composites reinforced with continuous stainless steel fibre (SSF) bundles. The mechanical properties of the composites were evaluated by short beam shear (SBS) testing to evaluate the interlaminar shear strength ( τ ILSS), along with Charpy impact testing. For both mechanical tests, two print orientations were examined: the flat, loaded perpendicularly to the printed layers, and the on-edge, loaded parallel to the printed layers. The PA11-SSF’s Charpy impact values were up to 83.9 and 73.1 kJ / m 2 for the on-edge and flat orientation 3D-printed orientations, respectively. The on-edge SBS testing also demonstrated higher τ ILSS of 24.9 MPa, compared with the 18.25 MPa obtained than the flat orientation. This difference in performance is associated with fibre distribution in the transverse versus the vertical (layer) directions. Thus demonstrating that to maximise the composite’s impact resistance, the continuous fibre orientation (on-edge or flat) needs to be considered in conjunction with the anticipated impact direction during a component design and printing. Studies carried out using an SBS system mounted inside an X-ray computed tomography system, facilitating the monitoring of the steel fibre deformation within the composite during loading. In addition, PA11-SSF composites, comparison mechanical testing was carried out on MEX 3D-printed Nylon 11, Nylon with short carbon fibre, and composites that combine short and continuous carbon.