Digital image correlation to reveal mechanical anisotropy in 3D printing of polymers

In this work, we propose to study the mechanical anisotropy inferred in printed acrylonitrile butadiene styrene polymer using fused deposition modelling by combining digital image correlation and mechanical testing. Tensile specimens are printed utilising different design orientations and raster angles. Monitoring of deformed samples is performed and strain fields are derived for each configuration. The results show that a heterogeneous strain field develops leading to a more significant strain localisation for samples printed with the dimensions mainly aligned with the building direction. An optimal printing angle allowing the filament to be crossed at −45°/+45° shows the best behaviour even with a larger elongation at fracture compared to the raw material. The digital image correlation based on optical imaging indicates, however, scaling limits to reveal the effect of the filament orientation on strain localisation.