On different 3D printing methods and fracture performance in DCB composite specimens including structured interfaces

This work experimentally analyzes the influence of the printing direction on the fracture resistance capabilities of composite specimens incorporating structured interfaces in their geometrical definition. In particular, we compare horizontal and vertical direction fiber deposition using 3D printing capabilities in order to identify the best scenarios that maximize the corresponding fracture performances. For this purpose, DCB specimens including improved structured interfaces designed with fiber in the profile region of the specimen are produced. These designs were created using 3D printing in long fiber composites. Experimental evidences reveal a remarkable increase in fracture toughness in structured interface profiles printed in the vertical direction compared to structured interface profiles printed in the horizontal direction, specifically 217% for the best configuration and 118% for the most unfavorable configuration. Present results show the potential benefits for the generation of novel design concepts with improvements in fracture resistance capabilities, fostering new perspectives in the definition of composite structures.