A novel optimised additively manufactured connection for hybrid semi-rigid lightweight steel framing

An innovative key-wheel (KW) connection comprising additive manufacturing (AM) wheel component is developed for a hybrid semi-rigid lightweight steel framing structure. The wheel components can be printed onto the web of the wall studs using either laser metal deposition (LMD) or wire arc additive manufacturing (WAAM). A genetic algorithm with multiple-objectives optimisation framework was employed to identify the optimal wheel geometries based on validated finite element method (FEM). For LMD connections, the objectives were to maximise the initial rotational stiffness, yielding strength and peak strength, while for WAAM connections an additional constraint was imposed by normalising these objectives with respect to material use. The optimisation results suggest a wheel shape with a greater number of elongated teeth for the proposed connection. The maximum joist deflections of the frame-level analysis are reduced by 16.5%-19.4% when employing the optimised connections, while the normalised initial stiffness, yield strength and peak strength are increased by 101.2%-103.9%, 166.7%-211.1% and 150.0%-158.3%, respectively.