High strain-rate failure mechanisms of additively manufactured IN718 Gyroid structures: Experiments and numerical insights

Architected materials based on triply periodic minimal surfaces (TPMS), such as Gyroid structures, are promising candidates for energy absorption applications in aerospace, defense, and biomedical fields due to their tailorable mechanical properties and lightweight design. However, their deformation and failure mechanisms under high-strain-rate loading remain poorly characterized, particularly regarding the influence of manufacturing defects and strain-rate sensitivity on damage localization. This study investigates the deformation and failure mechanisms of selective laser melting (SLM) IN718 Gyroid structures subjected to quasi-static ( ɛ ɛ ̇ = 0.008 s − 1 ) and high-strain-rate ( ɛ ɛ ̇ = 400 s − 1 and ɛ ɛ ̇ = 550 s − 1 ) compressive loading. The methodology integrates hydraulic press and Split Hopkinson Pressure Bar (SHPB) tests analysed through Digital Image Correlation (DIC) with Finite Element simulations, using an elasto-platic Johnson-Cook constitutive model to establish an ideal performance baseline. Five distinct mechanical regimes are identified, correlating the stress–strain response with the physical evolution of the structure. Quantitative results show that dynamic loading increases the post-peak force drop from 27.1% to 33.6%, highlighting an earlier onset of damage driven by inertia effects. Furthermore, the numerical-experimental comparison reveals an energy absorption deficit of approximately 17% for dynamic tests, illustrating the performance gap between idealized topologies and their corresponding SLM-manufactured specimens. These insights establish a framework for optimization strategies to enhance dynamic energy dissipation.