Compressive behavior of selective laser melting printed Gyroid structures under dynamic loading

The compressive behavior of a typical triply periodic minimal surface (TPMS) structure (Gyroid structure) fabricated by selective laser melting (SLM) is investigated experimentally and numerically under different loading rates. By using the digital imaging correlation (DIC) method, the deformation process is recorded to examine the deformation evolution in the specimens. The loading rate sensitivities of yield stress, plateau stress, and specific energy absorption are discussed accordingly. Meanwhile, numerical simulations are implemented by LSDYNA to reveal the deformation mechanism of the specimens in detail. Gyroid structures with different relative densities are calculated to capture the deformation patterns and discuss the relative density-stress relationship. Both the imperfect model reconstructed by CT photography and the idealized model originated from CAD file are adopted to explore the influences of printing defects on the mechanical performance of the cellular specimens. Additionally, the critical velocity and deformation transition of the printed structures are predicted through the rigid-linearly hardening plastic-locking (R-LHP-L) idealization model, while the reliability of the predicted results is validated by the numerical simulations. The results reveal that the 316L stainless steel Gyroid structures exhibit better energy absorption abilities compared with the other cellular materials, which appears to possess a widespread application in protective structures subjected to compression.