Effect of overlap joint position on strength of composite interlaminar reinforcement for fused filament fabrication 3D printer

Abstract

Fused filament fabrication (FFF) 3D printers have the advantages of being able to build complex structures automatically and at low cost. On the other hand, the tensile strength in the thickness direction is lower than that in the horizontal direction for objects fabricated by using fused filament fabrication 3D printers. In this study, we conducted mechanical evaluations by using an automatic strengthening method in which carbon-fiber-reinforced plastic (CFRPs) were embedded in the vertical direction in the form of joints, through 3D finite element method (FEM) simulations and experiments. We performed 3D FEM simulations on an analytical model with epoxy resin and two CFRP joints embedded inside polylactic acid, and confirmed that fracture occurred at the ends of the CFRP. The simulations showed that longer joint lengths and shorter distances between CFRPs increased the strength. Tensile testing of the specimens with CFRP embedded in the form of two CFRP joints showed that the maximum CFRP spacing affected the strength. This is consistent with the analysis results, which showed that the strength decreased with increasing CFRP spacing.