20.500.12556/DKUM-98251 Image-modulated implicit-field design of graded re-entrant triply periodical minimal surface with stabilised auxetic response This study examines the quasi-static compressive response of functionally graded auxetic triply periodic minimal surface (AUXTPMS) metamaterials designed to stabilise negative Poisson’s ratio behaviour at large strains. The proposed concept combines a re-entrant auxetic deformation mechanism with an in-plane porosity gradient generated through an image-modulated implicit-field workflow and isosurface extraction. Polymer (PA2200) and metal (stainless steel and aluminium) were tested in uniaxial compression, and transverse deformation was quantified using video image analysis complemented by digital image correlation. In contrast to uniform-porosity counterparts that exhibited early localisation and out-of-plane instability, the graded architectures promoted stable, sequential crushing and maintained a negative Poisson’s ratio over an extended strain range, with the re-entrant 1 × 1 configuration showing the most sustained auxetic response. Mechanical response analysis indicated that porosity gradation did not provide a universal increase in peak strength or stiffness-to-weight ratio, but it consistently improved deformation stability by suppressing out-of-plane buckling. Follow-on testing of the selected 1 × 1 design in aluminium and stainless steel demonstrated material-dependent specific energy absorption, reaching 2.63 and 5.05 J/g, respectively. Overall, the results identify porosity gradation as a key stabilisation strategy for practical auxetic TPMS architectures, enabling predictable deformation paths relevant to lightweight energy-absorbing and impact-mitigation applications. auxetic buckling gradation materials science metamaterial porosity specific energy transverse plane avksetične strukture upogibanje digitalna korelacija slik gradacija znanost o materialih meta materiali poroznost specifična energija prečna ravnina true false true Wiley Angleški jezik Slovenski jezik https://onlinelibrary.wiley.com/doi/10.1002/pssb.70249 Članek v reviji 2026-05-29 15:08:42 2026-05-29 15:08:43 2026-05-30 03:17:57 0000-00-00 00:00:00 2026 0 0 12 str. issue 5 Vol. 263 May 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-12-30 2026-05-13 2026-05-28 539.2:004.92 279818243 10.1002/pssb.70249 1521-3951 https://onlinelibrary.wiley.com/doi/10.1002/pssb.70249 1 3d89d125-5b5f-11f1-ad61-00155d580e34 https://dk.um.si/Dokument.php?lang=slv&id=206563 Physica_Status_Solidi_B.pdf Physica_Status_Solidi_B.pdf 1 B88F5FC29816695E00612E189EBEFFF6 b0e715d852960376ff72acdcf164e9e762c37fd99183105831ea0b5500ee59f9 bdda4d28-5b5f-11f1-ad61-00155d580e34 https://dk.um.si/Dokument.php?lang=slv&id=206564 Fakulteta za strojništvo 0 0 0