Design and Mechanical Properties of Layered Gradient Lattice Structures Based on Additive Manufacturing

Structural gradient changes are common in nature and play an important role in improving the carrying capacity of organisms. Graded lattice structures designed on this basis have received considerable attention due to their great design potential. In this study, two different layered gradient design strategies were proposed, and three lattice structures were designed. Samples with PA2200 nylon as the matrix material were prepared using additive manufacturing technology, and finite element models of the relevant lattice structures were established. The mechanical properties and energy absorption ability of the structures under different gradient spans and design strategies were investigated using quasi-static compression tests and numerical simulations. The results indicate that the layered design can improve the elastic modulus of the lattice structure by up to 40.05% and the energy absorption per unit volume by up to 13.04% compared to the conventional body-centered cubic (BCC) structure. However, it is worth noting that an excessively large interlayer gradient span can adversely affect the mechanical properties of the structure. In addition, all layered gradient lattice structures show significant anisotropy, and the energy absorption per unit volume can differ by up to 36.59% under different compression directions. The layered gradient structure design strategies proposed in this work can provide an effective reference for the design of gradient lattice structures.