Lattice structures are increasingly employed in lightweight engineering owing to their high strength-to-weight ratio and energy absorption (EA) capability. Their performance, however, depends strongly on topology and manufacturing quality. This paper presents a systematic experimental and analytical investigation of six polymeric lattice architectures fabricated by selective laser sintering (SLS), studied in both empty (EL) and polyurethane foam-filled (FFL) states, under compression. Results show that the PC-EL provides the highest strength but fails through brittle row-by-row collapse, whereas the HEX5-EL offers the best compromise between strength, stability, and EA. Foam filling drastically enhances performance, leading to stiffness increases of up to 40-fold and strength gains of nearly 100%. Notably, the PC-FFL absorbs 112 times more energy than its empty counterpart, while the WAF-FFL achieves the highest overall EA. Foam integration mitigates brittle failure by promoting stable, controlled deformation, thereby improving both integrity and specific properties. Predictive properties of modulus and strength are also proposed, extending the applicability of the findings beyond the tested cases. Overall, the study demonstrates that foam-filled SLS lattices, particularly PC and WAF, represent next-generation hybrid architectures with outstanding potential for load-bearing and EA applications in aerospace, automotive, and protective systems. • HEX5 lattice offers the best balance of strength, stability, and energy absorption. • Foam-filled lattices are up to 40 times stiffer and up to 99.9% stronger than ELs. • The PC-FFL absorbs 112 times more energy than its empty counterpart. • WAF-FFL has the highest energy absorption, while HEX5 and HEX3 absorb the least. • Foam filling mitigates brittle failure, enhancing mechanical performance.
Linul et al. (Tue,) studied this question.