Topology optimization method with elimination of enclosed voids

In this paper, a side constraint scheme is presented for topology optimization considering structural connectivity. Void features are used as basic design primitives with their movements and shape changes to drive topology optimization. To ensure the structural connectivity, design variables related to the centers of all the void features are bounded outside the design domain by means of side constraints without introducing additional nonlinear constraints. It is shown that the side constraint scheme is effective to eliminate enclosed voids and well adapted to the additive manufacturing (AM) without concern of unmelted powders inside the structure. Several representative examples are tested to demonstrate the effectiveness of the proposed method.