Low-speed impact penetration characterization of sheet-based triply periodic minimal surfaces

Designing lattice architectures with enhanced impact and penetration resistance is crucial for applications in aerospace, automotives, and protective equipment. Unlike prior studies focused on quasistatic or dynamic crushing, this work investigates the low-speed localized impact penetration response of triply periodic minimal surface (TPMS) sheet-based structures. Specifically, the response of additively manufactured AlSi10Mg alloy samples under moderate strain rate impact loading is analyzed. The samples, fabricated using the laser powder bed fusion (L-PBF) additive manufacturing technique, form a TPMS structure measuring 40 × 40 × 20 mm 3 from 10 mm unit cell arrays. The localized penetration testing was performed on the samples using a weighted drop tower equipped with a hemispherical impactor. This analysis assesses the penetration resistance of a total of seven topologies, having a constant relative density of roughly 28%. Furthermore, the influence of sub-optimal processing parameters on penetration resistance is also explored through a second set of TPMS samples. Key performance metrics including peak forces, maximum penetration depths, normalized absorbed energy and elastic stiffness were analyzed. Diamond and Gyroid TPMS exhibited the highest penetration resistance, with average penetration depths of 12.0 mm and 12.9 mm. Conversely, Lidinoid and Neovius samples were fully perforated, retaining residual kinetic energies above 30 J. Statistical analyses demonstrate that TPMS topology, processing parameters and fabrication quality substantially affect the penetration resistance of the TPMS structures. These insights can guide the design of lattice architectures optimized for impact-resistant applications, such as protective equipment.