Multi-material additive manufacturing: a computational design perspective

Multi-material additive manufacturing (MMAM) unlocks unprecedented opportunities in engineering, afforded by material and geometric complexity. However, leveraging its full potential necessitates advanced computational design tools tailored to specific application needs and fabrication techniques capable of translating digital designs into physical products with minimal discrepancy. This review provides a comprehensive evaluation of computational algorithms available for multi-material design, encompassing numerical methods like topology optimisation as well as data-driven inverse design strategies. MMAM techniques are evaluated for their multi-material design capability and manufacturing constraints. Key challenges in MMAM design are identified, including multi-material interface, advanced material response modelling, manufacturability, failure constraints, robustness, multifunctionality, and integrated design-manufacturing-validation workflow. Recommendations are made for incorporating these considerations into the optimisation framework. Future research directions are also suggested to pave the way for innovative multi-material applications.