Wet Twisting Treatment, Process Parameters Optimization and Mechanical Failure Mechanisms of 3d Printed Carbon Fiber Reinforced Composites

Abstract

The development of continuous carbon fiber (CCF) reinforced composites is essential to solve the problem of efficient stress transfer and realize the lightweight design and complex structure manufacture.3D printing technology promises to enable the molding of arbitrarily specified structures taking into account the CCF load transfer path and anisotropy. However, the inherent chemical inertness of CCF and the high viscosity of resins lead to interfacial bonding problems of prints.Consequently, optimization of the material and process is key to promote the mechanical properties. In this study, a CCF reinforced thermoplastic polyurethane (CCF/TPU) material system was constructed, which aiming at enhancing mechanical properties by 3D printing process parameters optimization, path planning and novel wet twisting pre-trement. Furthermore,the failure behaviors were explored to analyze the mechanism of the improvement of CCF impregnation degree, the reduction of forming defects and the improvement of interface bonding performance of prints. The results showed that the tensile strength and Young's modulus of CCF/TPU prints were 142.53 MPa and 20.92 GPa, when the nozzle temperature, printing speed, resin fiber ratio and bed temperature were 265℃,110 mm/min,130%, and 50℃,respectively. Additionally,the mechanical failure behavior of the prints were verified to be mainly fiber breakage under optimal printing parameters.Significantly,the tensile strength and elastic modulus of the CCF/TPU/PVDF prints with wet twisting were significantly improved by 62.18% and 87.16%, compared with the CCF/TPU prints without wet twisting.This strategy provides ideas for the improvement of mechanical properties of CFRP and expected to be applied in the field of energy absorption and vibration damping.

Keywords: continuous carbon fiber, 3D Printing, wet twisting treatment, process parameter optimization, mechanical properties