Design and multiscale simulation of Wool/PLA biocomposites: Experimental validation and impact failure analysis

• Developed a validated LS-DYNA model for wool/PLA biocomposites. • Combined impact and tensile tests with numerical simulations. • Revealed strong influence of fiber orientation on crack propagation. • Simulations provided insight into failure and energy dissipation. • Demonstrated potential of wool/PLA composites for lightweight design. This study presents numerical and experimental investigations of wool fiber-reinforced polylactide (PLA) biocomposites. In the first stage, a MAT_COMPOSITE_DAMAGE_54/55 (LS-DYNA) material model was developed based on mechanical tests performed on samples with two fiber-to-PLA mass ratios: W40/PLA60 and W60/PLA40. In the second stage, the models were applied in Charpy impact simulations to evaluate impact strength and identify dominant failure mechanisms. The results show that fiber content, orientation, and impact direction strongly influence energy absorption and failure behavior. Samples impacted along the fiber direction exhibited significantly higher strength and stiffness compared to transverse loading. Increasing PLA content enhanced stiffness and load-bearing capacity but led to more brittle failure. The W40/PLA60 composite absorbed the highest energy but failed abruptly, while W60/PLA40 exhibited a more gradual damage progression and distributed deformation of the composite structure. Microscopic analysis confirmed these differences, with fiber pull-out dominating in axial impacts and matrix cracking and delamination in transverse ones. The developed simulation model captures these behaviors and supports the structural design of Wool/PLA composites, offering a basis for future predictive modeling of sustainable biocomposites.