Interlaminar and translaminar fracture toughness of 3D-printed continuous fiber reinforced composites: A review and prospect

Fracture toughness is a critical parameter in the evaluation of a component's structural integrity and damage tolerance. For 3D-printed continuous fiber reinforced composites (CFRCs) based on the fused deposition modeling (FDM) technique, the fracture behavior differed from that of composites manufactured by traditional processes due to the presence of voids and interfaces at different scales, receiving significant attention. Recently published research attempted to apply various testing standards (for other materials) to investigate the fracture behavior of 3D-printed CFRCs. In these results, the fracture toughness of CFRCs was influenced by the manufacturing parameters dependent on structural porosity and interfacial bonding quality. This paper reviewed fracture toughness measurement standards compatible with CFRCs, factors influencing fracture behavior, and methods improving the fracture toughness of CFRCs. Lastly, this review explored limitations in current studies focused on fracture toughness measurement of 3D-printed CFRCs and future perspectives for the fabrication of 3D-printed CFRCs with improved fracture toughness.