Numerical and analytical modelling of a novel hybrid ductile connection between FRP composite elements

This paper presents the findings of numerical and analytical parametric studies conducted to investigate the mechanical behaviour of a novel hybrid ductile connection for FRP composite elements. The hybrid joints examined—recently patented—are designed to bond FRP components to steel elements. These steel components are assembled using ductile bolted joints that are intentionally designed to be weaker than the adhesive, thus promoting a controlled ductile failure mode. Among all the steel elements, there is a channel acting as a structural fuse in which deformation is concentrated, which can be easily disassembled and replaced when necessary. The numerical simulations provide valuable insights into the development of plastic deformation within the steel fuse. Building on these results, analytical models were formulated to derive simple equations for estimating the elastic and post-elastic stiffness, as well as the ultimate strength of the hybrid joints, as a function of component geometry. Comparisons among analytical predictions, experimental tests, and numerical response curves show good agreement, confirming the practical applicability of the proposed approach.