Mechanical characterization of 3D printed continuous carbon fiber reinforced thermoplastic composites

Three dimensional (3D) printing of continuous fiber reinforced composites has attracted great interest in various industrial applications, due to convenient complex geometry manufacturability and material savings. Understanding the mechanical properties of 3D printed composites is required for design and simulation. Hence, this paper aims to carry out a comprehensive study on tension, compression, bend and impact properties as well as failure behavior of 3D printed continuous carbon fiber reinforced thermoplastic (CCFRT) composites. The results show that the print fiber filament fill pattern significantly affect the mechanical properties of CCFRTs. Low strain rate has influence on failure mode and micro failure mechanism, but possesses no strong effect on the tensile elastic modulus and strength. Based on the data from longitudinal (0 degrees) and transverse (90 degrees) specimens, the mechanical properties of cross (0 degrees/90 degrees) specimens for three-point bend and unnotched Charpy impact can be predicted by the rule of mixing. However, it is not suitable for the notched specimens. The notch reduced the impact strength of cross specimens by 61.04%, indicating significant notch sensitivity. This study could provide some insights for testing and applying 3D printed continuous fiber composites.