Compression behavior of sheet-network triply periodic minimal surface metamaterials as a function of density grading

This study involved the fabrication and experimental testing of five distinct geometries of triply periodic minimal surface (TPMS) cellular structures characterized by uniform and relative density grading. The specific geometries examined were Schoen-Gyroid, Schwarz-Diamond, Schoen-I-WP, Schwarz-Primitive, and Fischer-Koch S. The experimental tests focused on subjecting these structures to compression loads. Samples were produced with a masked stereolithography (MSLA) printer. The samples had initial and end volume fractions (VFs) ranging from 20% to 60% in increments of 10%, with five varied relative densities. The Taguchi method is utilized to determine the optimal testing parameters, while the Analysis of Variance (ANOVA) test is employed to examine the data. The novelty of this paper is to comprehensively investigate the structural efficiency and versatility of TPMS for various applications by optimizing five different functionally graded TPMSs. The ANOVA findings highlighted the substantial impacts of Initial VF, Final VF, and TPMS type on the observed fluctuations in stress at the first peak. The Initial VF made a significant contribution, demonstrating 28.8% higher effectiveness than the Final VF. The TPMS type had a statistically significant effect on the amount of energy absorbed, revealing that different lattice types have abilities to absorb energy.