Numerical analysis of hybrid inter-module joints for enhanced seismic resilience of modular buildings

• Introduces HyMC™ to enhance seismic resilience in modular buildings. • Evaluates the impact of bolt size, material, and joint detailing. • High-fidelity FE model validated with experimental data for cyclic behaviour. • Shows stiffeners improve stress distribution but increase bolt demand. • Promotes damage-resistant, reconfigurable modular construction. The seismic resilience of steel modular building systems (MBSs) largely depends on the performance of inter-module connections (IMCs). Conventional IMCs, designed to remain elastic while plastic hinges form in beams, lead to significant residual drifts and permanent damage, limiting module reusability. To address these limitations, this study investigates the cyclic performance of a novel, recently patented, hybrid inter-module connection (HyMC™) and evaluates the influence of key design parameters, such as bolt size, material, and joint stiffness on its seismic behaviour. The connection incorporates a rubber bearing to mitigate damage and enhance post-earthquake functionality. A validated non-linear finite element (FE) model was developed to complement previous experimental work, providing detailed insights into force-transfer mechanisms, stress distribution, and the mechanical behaviour of the connection components. The FE simulations demonstrated strong agreement with experimental results, confirming the effectiveness of the HyMC™ in reducing residual deformations while maintaining structural integrity. The analysis showed that using larger bolt diameters and superelastic SMA studs effectively reduced stress concentrations and permanent deformations, while the addition of joint stiffeners redistributed stresses away from the beam–column zone but increased demands on the bolting assembly, highlighting the need for careful detailing. Future work should further optimise the joint design to enhance re-centring and energy dissipation and extend numerical studies to edge joints. This will support the development of simplified global models to evaluate the effect of the HyMC™ at the building level.