3D printing of high-strength continuous carbon fiber-reinforced composites with customized layers: Failure mechanisms and manufacturing validation
摘要整理
Continuous carbon fiber reinforced thermoplastic composites (CFRTCs) have excellent application prospects in aerospace owing to their outstanding lightweight and high strength. Nevertheless, it is necessary to conduct in-depth research on fiber ply designability and model fabrication validation. In this work, a dual-nozzle 3D printing process combined with designable fiber ply paths was adopted to prepare test specimens and mold complex structural parts. To explore the influences of matrix, carbon fiber and prepreg sizing agent on mechanical performance, interleaved and full-fiber layer specimens were manufactured for testing. The tensile strength of the full-fiber layer specimen (52 wt%) reaches 581.1 MPa, which is 213% higher than 185.8 MPa of the interleaved one (26 wt%). Its flexural strength reaches 351.1 MPa, 228% higher than 153.9 MPa of the interleaved specimen. The obvious performance difference derives from poorer interlaminar adhesion between matrix and sizing agent. Microscopic observation was carried out to analyze failure mechanisms from interlayer adhesion, fiber content and voids. The fiber path design method was further verified by manufacturing grille parts, which effectively optimized internal load transfer and mechanical bearing capacity. This study provides reliable experimental results and theoretical reference for the failure mechanism research and practical application of 3D-printed CFRTCs.