On the Design of Interference-Fitted and Adhesively Bonded Joints for Lightweight Structures

Interference-fitted and adhesively bonded joints are hybrid fastening systems that involve a hub (cylindrical or asymmetric) and a shaft (solid or hollow) locked together by both a frictional force (based on the radial pressure and the Coulomb friction law) and an adhesive strength generated at their coupling surfaces. Total interface forces allow the transmission of a high torque moment and/or a high axial force with respect to the joint dimension so that hybrid joints are demonstrated to be a smart solution for lightweight structures. This paper investigates the optimal combinations of geometrical parameters (ratios between internal and external diameters of the shaft and the hub) in order to maximize the axial load transmitted by the joint as well as to save the weight of the structure. Some design formulae, based on the maximum shear (Tresca) yield criterion, are proposed as a function of different materials for both the shaft and the hub (steel, aluminum, magnesium, and titanium)