Investigating the mechanical properties of 3D fused deposition modeling composites reinforced with continuous fibers: Effects of fiber number and negative Poisson structure

The use of 3D printers is expanding across various industries. The incorporation of reinforcing fibers and structures, such as negative Poisson, has the potential to enhance the mechanical properties of three-dimensional products. In this study, a specialized nozzle is developed for 3D Fused Deposition Modeling (FDM) printers dedicated to the production of continuous fiber-reinforced thermoplastic (CFRT) composites. The primary objective is to enhance the tensile strength and impact resistance of 3D-printed samples. It is achieved through the investigation of strategies such as fiber reinforcement, variation in the number of fibers within the reinforcing yarn, and the creation of samples featuring an internal structure with a negative Poisson’s ratio (NPRS). In this regard, four types of 3D samples are prepared including polymer only, polymer with a negative Poisson’s ratio structure, polymer reinforced with continuous fibers (glass and carbon fibers), and polymer reinforced with continuous fibers featuring a negative Poisson’s ratio structure. The mechanical properties of these samples, including tensile strength and impact resistance, are also compared. The results indicate that incorporating fibers as reinforcement can enhance the mechanical properties of 3D-printed products. Moreover, continuous fibers with more fibers within the same yarn count have an increased strengthening effect. The use of negative Poisson structures significantly improves impact resistance but adversely affects tensile strength.