Influence of the engagement ratio on the joint strength of press fitted and adhesively bonded specimens

Press fitted and adhesively bonded joints give several advantages: among others, they lead to smaller constructions for a given load capacity, or to stronger constructions for a given size. For that reason, the static and fatigue strength properties of these joints have been studied extensively. Studies dealing with the influence of the Engagement Ratio (i. e. the coupling length over the coupling diameter) are still limited. This work aims at filling the gap, limited to the case of a single component anaerobic adhesive. Coupling and decoupling tests have been performed both on press-fitted and adhesively bonded specimens and on pin-collar samples, considering four different levels for the engagement ratio. The study shows that the engagement ratio has a negligible effect on the shear strength of the adhesive and also on the relationship between the decoupling and the coupling forces. Moreover, the obtained results show that a too high interference level in press-fitted and adhesively bonded joints may have a detrimental effect on the adhesive strength.