Effect of build orientation and raster pattern on the fracture behavior of carbon fiber reinforced polymer composites fabricated by additive manufacturing

Abstract

Additive manufacturing (AM) process parameters highly affect the mechanical and fracture properties of additively manufactured carbon fiber reinforced polymer (CFRP) composites. In this work, we study the effect of two process parameters, including build orientation (XYZ, XZY, and ZXY) and raster pattern ( ± 45º and 0º/90º), on the fracture behavior of the CFRP composites fabricated by fused filament fabrication (FFF). The mode I fracture toughness and effective fracture energy of the CFRP composite materials are measured on compact tension samples. The crack growth direction in the FFF-fabricated CFRP composites is found to be controlled by both build orientation and raster pattern. The fracture toughness of the examined CFRP material is sensitive to build orientation, while the effective fracture energy reveals significant dependence on both build orientation and raster pattern. The samples fabricated with the XYZ and ZXY build orientations exhibit 5-fold greater effective fracture energy than the ones with the XZY build orientation. A wide range of fracture energy dissipation mechanisms, including fiber-bridging and fiber pull-out, are identified depending on the process parameters. The reported fracture trends in this study have the potential to provide guidelines for the development of FFF-fabricated CFRP composites with high fracture resistance.