Multiscale design for additive manufactured structures with solid coating and periodic infill pattern

Abstract

This paper considers multiscale topology optimization of an infill structure. The structure is composed of an optimized layout configuration at the macroscale with uniform optimized microstructures as infill lattices coated by a thin skin. The design optimization of the infill lattice is performed simultaneously with the topology optimization of macroscale structure, which also includes the coating. The classic Solid Isotropic Material with Penalization (SIMP) method is used to design the topology of the microstructure. The Novel Implementation of Asymptotic Homogenization (NIAH) evaluates the effective properties of the microstructure; the macroscale structural analysis uses these homogenized properties. The Porous Anisotropic Material with Penalization (PAMP) method realizes the two-scale topology optimization of the macrostructure and microstructure. Harmonic-mean based non-linear filters identify the coating layer and realize length scale control on the topologies of the macrostructure as well as the microstructure. These morphology mimicking non-linear filters also distinguish the skin and the infill lattice parts of the design at the macroscale. Several numerical examples demonstrate the effectiveness of the proposed optimization method.