Tailored Fiber Placements for Notch Sensitivity Study Using 3D Printing

Due to uninterrupted load transfer, continuous fiber composites have greater strength, stiffness, and toughness than nano, micro, and short fiber composites. Recent developments in 3D printing facilitated rapid manufacturing of thermoplastic composites with continuous fiber reinforcements. Such composites manufactured for primary structural applications are frequently subjected to perforations, notches, and fillets during joining and assembly processes, resulting in stress concentrations and, consequently, premature failure. As such, tailoring/steering the continuous fibers around the notch is anticipated to deliver better performance in strength and toughness as the fiber are not cut during the drilling process. In this investigation, three different cases were studied namely (i) Un-notched continuous glass fiber reinforced nylon composite (ii) Notched continuous glass fiber reinforced nylon composite and (iii) Steered continuous glass fiber around the notch. It was observed that drilling a circular notch size of size 0.3 (notch diameter/width of sample) can reduce the strength and strain to failure by 48 and 39 percent respectively. Nevertheless, samples with steered fiber around the notch manifested 22 percent improvement in strength and 38 percent improvement in toughness compared to the drilled samples. Overall, this technique provides an initial thumb-rule in enhancing the mechanical performance of continuous fiber reinforced composites.