Effect of three-dimensional loading on macroscopic fretting aspects of an aero-engine blade–disc dovetail interface

This paper investigates the effect of three-dimensional loading on macroscopic fretting variables, such as contact tractions, slip and contact stresses over the dovetail interface, carried out using three-dimensional finite element method with frictional contact at the interface. Three-dimensional loading effect is brought out by considering a skewed dovetail slot in the geometry and by application of forces and moments acting on the airfoil. The study reveals that a skewed (20°) dovetail experiences about 100% more peak contact pressure and slip amplitude than a straight dovetail slot. The peak contact pressure and contact stress are observed near contact edge, either at the leading or the trailing edge, for all the load cases studied for skewed dovetail. The contact traction, stress and slip variation along the dovetail are significant when compared with two-dimensional results. The study suggests that skew angle and three-dimensional loading need to be considered, for an improved understanding of the fretting aspects of a dovetail interface.

Research Highlights
► Effect of skew angle, friction and airfoil load on fretting of a dovetail interface is investigated.
► Contact tractions, stresses and slip was estimated by 3-Dimensional finite element analysis.
► A skewed dovetail exhibits higher peak contact pressure, slip amplitude than a straight dovetail.
► The peak contact pressure and stress is observed at leading / trailing edge of a skewed dovetail.