Predicting the Tensile Behavior of Basalt Fiber‐Reinforced Polylactic Acid ( PLA ) Biocomposites Using a Multiscale Modeling Approach

This study develops a micromechanical‐based multiscale modeling approach to predict the tensile behavior of basalt fiber (BF)‐reinforced polylactic acid (PLA) biocomposites. Biocomposites with fiber weight fractions of 5%, 10%, 20%, and 40% were fabricated via twin‐screw extrusion and injection molding. Experimental tensile tests showed that adding BFs significantly enhanced the mechanical performance of the brittle PLA matrix. The ultimate tensile strength expanded by 310%, increasing from 35.55 MPa for neat PLA to 145.88 MPa at 40 wt% fiber loading. Concurrently, the elastic modulus increased by 61.2%, from 3.35 to 5.40 GPa. Material toughness peaked at 1.29 MJ/m 3 for the 20 wt% composite (a ~600% enhancement) before decreasing to 1.05 MJ/m 3 at 40 wt% loading. SEM evaluation confirmed uniform fiber dispersion with an average aspect ratio of 18.22. Process‐induced fiber orientation tensors were computed via injection molding simulation and mapped to structural models (ANSYS) using Digimat mean‐field (Digimat‐MF) homogenization and Digimat‐MAP. This multiscale elastoplastic framework successfully captured the anisotropic structural response and predicted experimental failure loads across all fiber variations with high accuracy. The integrated approach provides a reliable, data‐driven design tool for high‐performance structural biocomposites.