Three-dimensional (3D) printing is a promising technology that can produce complex structures without the requirements of expensive tools and molds. Additives are usually incorporated into the plastic materials used in 3D printing to increase their strength and rigidity. Particularly, carbon fiber-reinforced plastic (CFRP) has shown great promise as a 3D printing material. However, the strength of CFRP after printing remains unknown, although it is well-known that its strength is affected by plastic melting during printing. Herein, we analyzed the fracture behavior of CFRP specimens before and after bending to different curvature radii. From the experimental results, a fracture criterion describing the material behavior by considering the tensile and compressive loads was developed. The fracture mechanism remained the same for CFRP specimens with different curvature radii. This study deepened our understanding of the mechanical properties of CFRP materials used in 3D printing.
