Multi-material topology optimization of coated structures using level set method

Abstract

The coated structures are widely applied in engineering, whose coating material covers the surface to protect substrate structure or realize certain functionalities. Currently, the coated structures are generally filled with uniform material. Moreover, the multi-material infill structures can further improve their performances. Therefore, this paper proposes a level set topology optimization method to design the coated structures with multiple infill materials. The coating material with uniform thickness is required to attach the outside of the substrate structure, which can be seen as a manufacturing constraint. In particular, we demonstrate how to construct the multi-material infill structures and formulate the multi-material interpolation model by combining multiple level set functions. Besides, the shape derivatives for the multi-material optimization model of the coated structures are derived for the first time. Finally, numerical examples confirm that the coated structures with multiple infill materials can be effectively obtained by using the proposed method.