Efficient and exquisite concurrent optimization of hierarchical structures with non-uniform eccentric body centered cubic lattice

Abstract

To obtain lightweight structures with desirable mechanical performances and to enlarge the design space, this work presents an innovative concurrent optimization methodology for the precise inverse design of micro lattices and the modeling of hierarchical structures. The inverse design of micro lattices with continuously changing anisotropic properties is achieved by offsetting the center nodes of eccentric body centered cubic lattices (EBCC) to designated locations. Simultaneously, the macro material distribution is adjusted utilizing 3D density-based topology optimization method. To enhance the computation efficiency and significantly amplify the versatility in optimization design, a Parameterized Interpolation for Anisotropic Lattice material (PIAL) is established based on elastic stiffness matrices of micro lattices with 21 independent components. Specifically, a cubic multinomial function is employed to construct a direct correlation between micro topology configurations and equivalent elasticities of the EBCC lattices. Several numerical examples of compliance optimization are carried out to confirm the validity of the proposed approach. Concurrently, Additive Manufacturing (AM) using AlSi10Mg is adopted to manufacture the obtained hierarchical structures, which exhibit well-improved mechanical performance, as confirmed by experimental testing, when compared to the classical density-graded structures.