Lattice Structures Design by Means of Topology Optimization

Abstract

In recent years, research and development of lattice structures have gained much attention because of their unique functional characteristics such as high compliance, high specific strength, and enhanced heat transfer. One promising strategy for new developments is to use topology optimization as a design tool to obtain new unit cells for lattice material. However, this approach may lead to optimal topologies with highly complex geometries and traditional manufacturing processes may no longer be feasible in these cases. Additive manufacturing (AM) techniques may fill the gaps between topology optimization and product by removing the geometric complexity restriction to a large extent. Even so, their manufacturing constraints, such as feature size and maximum inclination angle for building a product, need to be considered in the optimization process. In the effort to address the design of lattice infill, different approaches have been developed. A simple approach, called variable-density lattice structure optimization, is to perform a single-scale topology optimization and fill the interior with a prescribed base shaped unit lattice. The two-scale topology optimization approach optimizes both the macro and micro-scale, allowing the unit cell freely change. In this paper, we present a study on the variable-density lattice structure optimization.