Dr. Shahadat Hussain

Triply periodic minimal surface (TPMS) lattices offer high structural efficiency for lightweight energy absorption, yet the effects of chopped fiber reinforcement and post-processing on their mechanical response remain poorly quantified. This study systematically investigates the mechanical behavior of additively manufactured gyroid TPMS lattices fabricated from five polymeric filaments —VeroWhite, Nylon 12, ABS, Carbon Fiber-reinforced PLA (PLA-CF) and polyphthalamide (PPA-CF)— across relative densities of 20–40%. Experimental results show that annealed fiber-reinforced lattices, particularly PPA-CF, consistently outperform unreinforced polymers in terms of peak stress, toughness, and energy absorption, with performance gains becoming more pronounced at higher relative densities. Post-print thermal annealing of PPA-CF increases its peak stress by 40% and toughness by up to 60%, while altering its post-yield deformation stability. Annealed PPA-CF gyroids achieve specific energy absorption values of up to 24–25 kJ/kg at densities of 200–430 kg/m³, comparable to reported metallic TPMS structures, at substantially lower weight. Finite element analysis reveals elevated stress localization and increased plastic strains in fiber-reinforced lattices, consistent with the experimentally recorded post-elastic ductility trade-offs. These findings demonstrate that chopped fiber CF reinforcement, in combination with thermal post-processing, fundamentally modifies deformation behavior and enables high performance, lightweight TPMS architectures through coordinated control of relative density and processing.