A comprehensive study of feature definitions with solids and voids for topology optimization

In this paper, we present a CAD-oriented and feature-driven topology optimization methodology for engineering structures with freeform design domains. Mixed solid–void features are adopted as basic design primitives to build a unified formulation of feature definition, while pure solid or pure void features are considered as two special cases. Topology optimization is achieved as a Boolean intersection process between the so-called topology variation modeler (TVM) and freeform design domain modeler (FDDM) in terms of level-set functions (LSFs). The TVMs constructed with solid and/or void features are applied to clip the FDDM through Boolean operations. It is shown that sensitivity analysis with boundary integral scheme is independent of the mathematical expressions of the LSF. Numerical problems with freeform and periodic design domains are dealt with to demonstrate the proposed topology optimization method.