Theory of critical distances and notched filament-based 3D-printed components: lessons learned from polymers and concrete

The present paper reviews the work we did in recent years (Ahmed and Susmel, 2018, 2019; Alanzi et al., 2022) – to use the Theory of Critical Distances to model the detrimental effect of manufacturing defects and voids in 3D-printed concrete/polymers subjected to static loading. The validity and robustness of the proposed approach is assessed against a large number of experimental results that were generated by testing 3D-printed specimens of both concrete and polylactide (PLA) containing manufacturing defects/voids. The sound agreement between experiments and predictive model makes it evident that the Theory of Critical Distances (TCD) is not only a reliable design approach, but also a powerful tool suitable for guiding and informing effectively the additive manufacturing process.