Topology optimization for 3D concrete printing with various manufacturing constraints

The integration between 3D concrete printing (3DCP) and topology optimization (TO) enables the fabrication of structurally efficient components without expensive formwork and intensive labor. However, manufacturing constraints of 3DCP are impeding the integration between the two fields, and there has been limited research on this topic. In this paper, we address various manufacturing constraints of 3DCP within the bi-directional evolutionary structural optimization (BESO) framework. Firstly, a layer-wise sensitivity scheme is proposed to generate self-supporting designs in the user-defined print direction. Secondly, a novel continuous extrusion constraint is implemented to facilitate the continuous printing operation of the design. Thirdly, the anisotropy of the 3DCP process is simulated during optimization by employing a transverse isotropic material model. Fourthly, domain segmentation is introduced to facilitate modular construction, and each partitioned segment can be assigned with its favorable print direction. Finally, the algorithm's feasibility is demonstrated by constructing a topology optimized chair.