Numerical and Experimental Investigation of Failure Mechanisms in Additively Manufactured Multimaterial Triply Periodic Minimal Surface Polymer Cellular Materials

Triply periodic minimal surface (TPMS) lattices are an emerging class of cellular materials with excellent potential for lightweight structural and energy‐absorbing applications. In this study, gyroid (G), diamond (D), and primitive (P) architectures were fabricated via fused filament fabrication (FFF) using three material configurations: (i) single‐phase polylactic acid (PLA) or polyethylene terephthalate glycol (PETG); (ii) layered PLA‐PETG composite structures (50/50), in which the lower half was printed with PLA and the upper half with PETG; and (iii) layered composites with PLA shells and PETG cores. Quasi‐static compression tests were combined with finite element simulations to elucidate stress distribution, deformation mechanisms, and collapse progression. The results demonstrate that homogeneous blends delay crack initiation and enhance specific energy absorption through progressive collapse, while layered composites improve stability by redirecting stresses via the PLA shell. Finite element analysis successfully captured shear banding, layer‐wise buckling, and localized fracture, confirming the predictive capability of the simulations. The findings highlight the strong interplay between lattice geometry and material configuration in tailoring mechanical performance and provide guidelines for the design of multifunctional polymer‐based cellular composites produced by additive manufacturing.