Introduction

A novel approach based on multiscale topology optimization to design stiff and robust components using a limited amount of material, simultaneously defining i) boundaries of the element and ii) internal arrangements of circular/spherical holes with graded radius that can be effectively 3D-printed.

Technical features

The methodology allows generating optimal 2D or 3D components (any object subject to loads and constraints, e.g. mechanical parts, structural components, elements of the building envelope, design pieces, industrial design objects, …) that are especially conceived for fabrication with Additive Manufacturing (AM) techniques working by layers such as Fused Deposition Modelling (FDM). Indeed, circular/spherical holes in Hexagonal Close-Packed (HCP) arrangements allow defining an isotropic/transversely isotropic graded microstructure that can be effectively printed without the need for extended supports to be added during the printing process. Benefits of the proposed methodology are expected also for other AM techniques, such as metal printing. Due to the static indeterminacy of the microstructure, robust results are found (more than one load path arises in the optimal design). An efficient algorithm is coded that takes design domain and boundary conditions as input to write an output file containing the printable geometry for AM. Also, when boundaries of a hollow component are prescribed i), the algorithm can be used to equip it with an optimal microstructure ii).

Possible Applications

• Automotive and aerospace;
• Biomedicine;
• Architecture, design, and fashion.

Advantages

• Structural components conceived for additive manufacturing;
• Enhanced structural stiffness;
• Decreased stress concentration in the final layouts, with increased robustness;
• Remarkable reduction of support structures needed for the printing process.