Generative design of structural frame joints

Application of topology optimisation as an advanced engineering tool can be extended advantageously in exploring design solutions for structures aimed to be fabricated through Additive Manufacturing (AM). While the conventional engineering approach towards the design and fabrication of structural joints offers limited opportunities for enhancement of their primary characteristics, such as strength, stiffness and ductility, topology optimisation can allow engineers to explore solutions of higher structural efficiency with the same material quantity. This study explores the capabilities of combining structural topology optimisation and additive manufacturing in the advanced design of structural frame joints with superior structural characteristics. An augmented framework of the Bi-directional Evolutionary Structural Optimisation (BESO) scheme based on discrete design variables is adopted to deliver optimised solutions for the connections. It is shown that integrating the material and geometric non-linearities into the optimisation process, enhances the structural performance of joints in terms of strength and ductility. Hence, as distinct from the common assumption of a linear structural response, in the optimisation of steel structural components for ultimate limit state design, the optimisation should account for geometric and material non-linearities. Furthermore, the adoption of optimised joints in frame structures is shown to reduce deflections and decrease design actions in the connecting beam members which results in more economic designs. • A practical process for achieving a generative design for frame joints via structural optimisation. • Superiority of optimised joints is shown compared to conventionally designed and manufactured steel joints. • Including non-linearities in optimisation benefits ultimate limit state design and should be considered. • Higher stiffness in optimised joints reduces beam deformations and design forces.