Multiscale Prediction of Anisotropic Plasticity in Additively Manufactured Lattices

ABSTRACT Homogenization‐based modeling of additively manufactured lattice structures has predominantly focused on elastic behaviour, while reliable prediction of anisotropic plasticity remains limited. This study presents a multiscale numerical framework for predicting the elastic–plastic response of fused filament fabrication (FFF)‐printed polymer lattices by combining representative volume element (RVE)‐based homogenization with the Hill anisotropic yield criterion. Realistic filament‐level RVEs, incorporating bead geometry, inter‐bead overlap, and layer stacking, are subjected to three normal and three shear loading cases under periodic boundary conditions to extract effective orthotropic elastic constants and direction‐dependent yield stress ratios. These homogenized properties are transferred to a macroscale finite‐element model of three‐point bending, where anisotropic yielding is implemented through the Hill criterion. The proposed framework is validated in two stages: (i) comparison with explicit filament‐resolved microstructural finite‐element simulations, and (ii) correlation with experimental three‐point bending tests measured using digital image correlation. Results demonstrate good agreement in load–displacement response, strain localization, and yield onset across different raster orientations, build configurations, and infill patterns. The approach achieves substantial computational efficiency while preserving the essential anisotropic plastic behaviour governed by filament architecture and interlayer bonding. This multiscale methodology provides a practical tool for the design, analysis, and optimization of load‐bearing FFF‐printed lattice structures.