Topology optimization for staged construction

This paper presents a topology optimization formulation that accounts for construction in stages. Unlike in common topology optimization procedures, the loading and support conditions during construction are considered in addition to the final situation for which the structure is intended. The main purpose is to generate optimized layouts that can be built without temporary supports or scaffolds, as required for example in the design of segmental bridges. Another field of application which can benefit from this formulation is the design for manufacturing by layers, for which the staged construction is interpreted as a layer-by-layer fabrication process. By slicing the design domain and considering several fabrication stages, we obtain optimized designs that are influenced by the building direction and by the excessive deformation of unsupported layers. Demonstrative examples in 2-D and 3-D show that the amount of temporary scaffolds which are required for supporting during construction can be reduced significantly. Finally, we apply the layered approach to the design of hybrid void-support-solid layouts that can exhibit superior balance between performance and constructability compared to void-solid topologies.