Mechanical properties of the composite lattice structure with variable density and multi-configuration.

• A new composite lattice structure with variable density and multi-configuration arrangement. • Lattice cells with different configurations are arranged in different regions. • The thin rods of cells were improved by cell replacement. • The composite arrangement further enhances the mechanical properties of lattice materials. A new composite lattice structure is proposed by combining variable density and multi-configuration arrangement. The parameter mapping model is established, and three composite lattice structure models are presented. The samples are prepared by the additive manufacturing technology SLS (Selective Laser Sintering) with Nylon PA6. The samples are tested by the universal testing machine and drop weight impact testing system. The load-deformation, equivalent impact load and failure mode are analyzed. The results show that compared with the variable density lattice structure, composite model 1 (GBCC cells in the low-density region are replaced by ECC cells) improves the thin rods in the low-density region, composite model 2 (the cell sizes in the high-density region are increased while GBCC cells in the low-density region are replaced by ECC cells) increases the equivalent bending stiffness by 8%, enhances the bending and impact deformation resistance of materials, and composite model 3 (GBCC cells in the high-density region are replaced by BCCxy cells) increases the failure load by 77%, reduces the equivalent impact load by 47%, and improves the toughness and cushioning performance of materials. This work finds that the composite lattice structure with variable density and multi-configuration further improves the mechanical property of lattice materials. [ABSTRACT FROM AUTHOR]