Torsional Performance of 3D Printed Nylon Carbon Fiber Reinforced Composites

Composite materials are commonly used in aerostructures in order to achieve increased structural performance coupled with a reduction in weight. Additive manufacturing is a rapidly growing manufacturing method for composite materials, due to its ability to develop components with more complex geometries at a relatively lower cost. Nylon composites are commonly used in aerostructural applications, which are subject to torsional loading conditions. Research regarding the monotonic torsional response of additively manufactured nylon and nylon composites reinforced with continuous carbon fibers (CCF) is limited. Most existing research studies have reported on the tensile and flexural performance of these polymer matrix composites. However, these benefits come with some limitations, such as the presence of voids, unbonded filament layers, and poor adhesion between fiber and matrix material which can affect the mechanical performance of these additively manufactured materials. This study is novel in that it explores the torsional response of 3D-printed nylon and nylon reinforced with continuous carbon fibers, and the role of additive manufacturing induced microstructural defects on torsional performance, hence bridging this research gap. Results show that the incorporation of continuous carbon fiber increases the shear strength and stiffness of nylon, while decreasing the ductility. Upon failure, pure nylon samples exhibited a form of buckling while nylon carbon fiber samples exhibited evidence of carbon fiber pullout.