Adjustable Energy Absorption of Triply Periodic Minimal Surface Structures via Additively Reconfigurable Manufacturing-Based Investment Casting

Structures with triply periodic minimal surfaces (TPMS) are characterized by continuous and smooth geometries, providing design versatility well-suited for mechanical enhancement and energy dissipation functions. Although metal additive manufacturing (AM) is a powerful method for fabricating TPMS structures, its application at large scales is often limited by high production costs, build size constraints, and challenges in achieving fully dense structures in complex enclosed geometries. To address these practical limitations, this study proposes a modular investment casting strategy using 3D-printed polylactic acid patterns to fabricate Schwarz Primitive TPMS structures. By decomposing the structure into castable modules, the proposed method enables flexible scaling while reducing common casting defects such as cold shuts and incomplete filling. Six configurations with different wall thicknesses and unit cell counts are successfully produced. Experimental results demonstrate that increasing the wall thickness significantly enhances the yield strength, elastic modulus, and energy absorption, with the best-performing specimen exhibiting a specific energy absorption of 19.9 J g⁻¹. Compared with conventional lattice topologies and stainless-steel cellular metal foams, the modular TPMS structures demonstrate superior tunable energy absorption in the high-density regime (1.8–3.5 g cm⁻³). This work establishes a cost-effective and scalable alternative to AM for manufacturing high-performance TPMS structures for engineering applications.