3D printing single-stroke path planning, local reinforcement and performance testing of MBB beams and cantilever beams

3D printing of continuous fiber reinforced thermoplastic composites (CFRTPCs) has been applied for the molding of composite complex structures due to the advantages of flexibility and one-step forming. In this study, feature points simplification, merging and rearrangement were accomplished for Messerschmitt-Bölkow-Blohm (MBB) beam and cantilever beam to generate single-stroke print paths for the specimens. For the significant stress areas in the finite element analysis results of these structures, a local reinforcement method using orthogonal layups was proposed, which was achieved by raising and lowering the print head and adjusting the fiber volume fraction during the printing. After experimental validation and failure modes analysis, the path planning significantly improved the peak load and structural stiffness of the specimens, and the local reinforcement further enhanced the equivalent specific strength and specific stiffness. This study provides a single-stroke 3D printing strategy for complex structure molding in conjunction with parameter adjustments. Highlights: A single-stroke path planning was developed for MBB beams and cantilever beams, including simplification, merging and rearrangement methods for feature points. A local reinforcement method was proposed, which was achieved by raising and lowering the print head and adjusting the fiber volume fraction during the printing process. The effect of different print paths on specimen properties was investigated.