Analytical probabilistic progressive damage modeling of single composite filaments of material extrusion

This research focuses on investigating the elastic and damage characteristics of individual composite beads utilized in additively manufactured (3D printed) composites. A novel analytical probabilistic progressive damage model (PPDM) is introduced to comprehensively capture the elastic and damage attributes of these
single 3D printed beads, which constitute the foundational elements of 3D printed composites. The PPDM is formulated based on assumptions of a perfectly elastic, perfectly plastic, and elasto-plastic matrix. For the elasto-plastic matrix, a novel formulation of the damage is developed to offer a more realistic view of the
internal mechanics. Furthermore, a novel method of measuring the Young’s modulus of 3D printed composites is assessed. To this end, the Sentmanat extensional rheometer (SER) fixture is used to conduct a series of tensile
tests on Kevlar and glass fiber-reinforced nylon beads. The experimental data of the SER are compared with those from an Instron tensile machine. Finally, the results of the PPDM and the experiments are compared and reveal a strong agreement in both the elastic region and the ultimate strength and strain.