Influence of Infill Density and Orientation on the Tensile and Viscoelastic Response of Additively Manufactured PLA

This is a collaborative project with the University of Glasgow and investigates the mechanical behaviour of polylactic acid (PLA) specimens manufactured via fused deposition modeling (FDM), focusing on how infill density and infill orientation influence their tensile and time-dependent viscoelastic responses. Specimens were fabricated with infill densities of 25%, 50%, and 100%, and with orientations of 90°/0° and 45°/–45°, designed to alter the internal shear load distribution during tensile deformation.

A comprehensive experimental campaign was conducted, including quasi-static tensile tests, strain rate sensitivity evaluations, and stress relaxation experiments. The aim is to assess both the immediate mechanical performance and the viscoelastic behaviour of the material under in-service loading conditions. The influence of internal structure on stiffness, strength, and time-dependent deformation was quantified. The project will inform material parameters for non-homogeneous geometries in computational investigations using Abaqus.