Large-scale additive manufacturing of optimally-embedded spinodal material architectures

We present a synergistic methodology to design large-scale 3D-printed structures based on a multi-material topology optimization formulation, which leads to the realization of three-dimensional hierarchical structures with spatially oriented non-periodic spinodal microstructures. The inherent characteristics of these unstructured architectures allow the design of optimized layouts with smooth transitions of spinodal material classes, accounting for varying porosity and orientation. The design and manufacturing processes are bridged by a topology-by-material optimization approach, in which the iterative process preserves the macro-scale continuity, while the microstructural topological space is optimized by a suitable distribution of multiple spinodal architected materials. To illustrate both the design and the manufacturing processes, we leverage the features of a large-scale water jetting powder-bed 3D printing technology, which makes use of aggregates obtained from powdered stone-like materials and magnesium-based binders. The optimized model is transferred to the printer by means of a voxel-based generation strategy. The approach, exemplified by means of several numerical simulations and physical 3D-printed samples, connects design conceptualization, material properties at different length scales, and the complex process of additively manufacturing load-bearing structures in a large-scale framework.