Through the thickness mechanical characterization of 3D printed composite polymers

The present study aims at investigating the mechanical behavior of 3D printed composites through their thickness by embedding multiple fiber Bragg grating (FBG) sensors within the built structures. Dogbone composite samples were fabricated via the Fused Deposition Modeling (FDM) process using short carbon fiber-reinforced polyamide (CF-PA) material. The FBGs were embedded into various positions across the test coupons’ thickness, which consisted of 16 layers with a raster orientation of 0 o (parallel to the long axis). The samples were then subjected to tensile testing to obtain stress-strain curves from the FBG measurements, which were compared to the extensometer data. Moreover, in-process generated temperature profiles were also monitored to better understand their effect on the specimens’ fabrication-induced residual strains and corresponding mechanical behavior. Microscopy analysis was also performed to evaluate the quality of FBG sensors’ embedment within the host composite material. The experimental results demonstrate that FBG sensors can be effectively used for the calculation of the Young’s modulus of FDM-fabricated composites and, in general, for FDM structures’ mechanical characterization.