Nonlinear coarse-graining models for 3D printed multi-material biomimetic composites

• DOI: 10.1016/j.addma.2022.103062
• Publication Date: 2022-07-30T07:48:40Z
• Authors: Mauricio Cruz Sal...; Eugeni L. Doubrovski; Mohammad J. Mirzaali; Amir A. Zadpoor
• Keywords: Bioinspired; Coarse-grained model; Condensed Matter - Materials Science; Multi-material; 0103 physical sciences; Voxel-based; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 3D printing; Bitmap; 01 natural sciences; Biomimetic Material

Bio-inspired composites are a great promise for mimicking the extraordinary and highly efficient properties of natural materials. Recent developments in voxel-by-voxel 3D printing have enabled extreme levels of control over the material deposition, yielding complex micro-architected materials. However, spatial complexity makes it a formidable challenge to find the optimal distribution of both hard and soft phases. To address this, a nonlinear coarse-graining approach is developed, where foam-based constitutive equations are used to predict the mechanics of biomimetic composites. The proposed approach is validated by comparing coarse-grained finite element predictions against full-field strain distributions measured using digital image correlation. To evaluate the degree of coarse-graining on model accuracy, pre-notched specimens decorated with a binarized version of a renowned painting were modeled. Subsequently, coarse-graining is used to predict the fracture behavior of bio-inspired composites incorporating complex designs, such as functional gradients and hierarchical organizations. Finally, as a showcase of the proposed approach, the inverse coarse-graining is combined with a theoretical model of bone tissue adaptation to optimize the microarchitecture of a 3D-printed femur. The predicted properties were in exceptionally good agreement with the corresponding experimental results. Therefore, the coarse-graining method allows the design of advanced architected materials with tunable and predictable properties.<br/>Original article<br/>