Energy absorption and deformation characteristics of eight SLS-manufactured PA12 lattice structures under an intermediate compressive load rate

Abstract The mechanical response of additively manufactured (AM) lattice structures (LSs) under intermediate loading rates is crucial for real-world applications involving loading rates between quasi-static and high-speed impacts. Testing AM LSs in this regime ensures that the mechanical response aligns with operational conditions. Furthermore, powder entrapment within AM-processed LSs can change their effective porosity, consequently changing their targeted properties. This research aims to investigate the effects of an intermediate load rate and entrapped powder on the compressive behaviour and energy absorption characteristics of four strut-based LSs, namely, BCC, IsoTruss, Octet, and Diamond, and four sheet-based triply periodic minimal surfaces (TPMS) LSs, namely, Schwarz Primitive, Gyroid, Schwarz Diamond, and Split-P, manufactured by SLS from PA12 powder. Strut-based LSs exhibited minimal powder entrapment, while TPMS LSs had increased density from excessive trapped powder. Under intermediate loading, the strut-based lattices, except for IsoTruss, failed catastrophically. In contrast, imperfectly cleaned TPMS LSs exhibited remarkable stiffness, and higher compressive plasticity resulted in high load absorption capacity under intermediate load as the entrapped powder worked as a secondary control of energy storage and stiffness. These findings provide valuable insights into the impact of intermediate loading and entrapped powder on the energy absorption characteristics of SLSed PA12 LSs.