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A heterogeneous lattice material composed of different cells is proposed to improve the energy absorption capacity. The heterogeneous structure is formed by setting layers of body-centered XY rods (BCCxy) cells as the reinforcement in the body-centered cubic (GBCC) uniform lattice material. The heterogeneous lattice samples are designed and processed by additive manufacturing technology. The stress wave propagation and energy absorption properties of heterogeneous lattice materials under impact load are analyzed by finite element simulation (FES) and Hopkinson pressure bar (SHPB) experiments. The results show that, compared with the GBCC uniform lattice material, the spreading velocity of the stress of the (GBCC)3(BCCxy)2 heterogeneous lattice material is reduced by 18.1%, the impact time is prolonged 27.9%, the stress peak of the transmitted bar is reduced by 34.8%, and the strain energy peak is reduced by 29.7%. It indicates that the heterogeneous lattice materials are able to reduce the spreading velocity of stress and improve the energy absorption capacity. In addition, the number of layers of reinforcement is an important factor affecting the stress wave propagation and energy absorption properties. [ABSTRACT FROM AUTHOR]

• 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]