Design for Additive Manufacturing of Functionally Graded Lattice Structures: A Design Method with Process Induced Anisotropy Consideration

Abstract

Lattice structures are well-known as a solution for designing parts with lightweight and multifunctional characteristics. Owing to the advancement of additive manufacturing (AM), the development of design methods for additively manufactured lattice structures has extensively progressed, especially for functionally graded lattice structures (FGLS). Despite plenty of available design frameworks, the application of AM constraints in the design of FGLS is limited to geometric issues. Further, there is a lack of design methods that consider the unique physical properties of additively manufactured parts, especially the anisotropic characteristics induced by AM processes. This paper proposes a novel method for the design of additively manufactured functionally graded lattice structures with the consideration of AM anisotropic properties. In addition, a customized anisotropic AM-Lattice material model that supports the design of FGLS through the density-variable topology optimization is proposed. Moreover, Fused Deposition Modeling (FDM) process in which the process-induced anisotropy of AM is clearly demonstrated is focused. The design method was validated by the three-point bending-beam design problem, a classical design problem for validating topology optimization. The results, showing agreements between simulations and experiments, prove the validity and practicality of the proposed method.