Strength-based concurrent design for structural topology and building orientation of additively manufactured lattice structure

A novel Additive Manufacturing (AM)-driven concurrent design strategy based on the beam characterization model considering strength constraints is proposed. The lattice topology, radius size, Building Orientation (BO), and structural yield strength can be simultaneously adjusted by integrating the overall process-structure-performance relationship of the AM process into the optimization. Specifically, the transverse isotropic material model is adopted to describe the material properties induced by the layer-by-layer manner of additive manufacturing. To bolster lattice strength performance, the stress constraints and ratio constraints of lattice struts are employed. The Tsai-Wu yield criterion is implemented to characterize the lattice strut's strength, while the P-norm method streamlines the handling of multiple constraints, minimizing computational overhead. Moreover, the gradient-based optimization model is established, where both the individual struts diameters and BO can be designed, and the buckling-prone spatial struts are strategically eliminated to improve the lattice strength further. Furthermore, several typical structures are optimized to verify the effectiveness of the proposed method. The optimized results are quite encouraging since the heterogeneous lattice structures with optimized BO obtained by the strength-based concurrent method show a remarkably improved performance compared to traditional designs.