Effects of Printing Paths on Compressive Strength of 3D-Printed Continuous Fiber-Reinforced Composite Lattice Unit Cell

Three-dimensional printing is a highly promising manufacturing technology that enables easy production of complex shapes. Composite lattice structures are highly efficient, having the advantages of fiber-reinforced composites and the excellent structural performance of lattice configurations. Highly efficient structures can be developed by combining the benefits of 3D printing and composite lattice structures. This study examined the effect of printing path and axial angle in joint areas on the compressive strength of composite lattice unit cells fabricated via continuous fiber 3D printing. Compression tests were conducted to analyze deformation, failure modes, and causes of failure. A finite element model was used to analyze buckling behavior and establish design criteria. Results showed that the printing path significantly influenced failure mode and strength, while a fabrication method without a defect at the joint was important for improving structural performance. Finally, design criteria, in terms of the knockdown factor and in-plane bifurcation buckling behavior, were developed based on experimental and numerical results.