An investigation into the effect of contact geometry on the rotary bending fretting fatigue life of Al 7075-T6

Abstract

The effect of contact geometry on the rotary bending fretting fatigue of Al 7075-T6 has been investigated. Two types of contact geometries, conforming and non-conforming, have been considered in the investigation. Three different characteristic lengths have been used for each type of contact. In the conforming type, three different contact areas and in the non-conforming type three different fillet radii has been considered in this work. The results show that bending fretting fatigue reduces the life of the material by about 90% in some cases. The reduction varies with the contact type and characteristic length. In the conforming type of contact, fretting fatigue life increases with the increase of characteristic length for low bending stresses but at higher bending stresses the fatigue life converges to the same cycles, regardless of the characteristic length. In the non-conforming type, fretting fatigue life reaches a minimum at the fillet radius of 1.5 mm. Since, contact pressure, shear stress, and slip amplitude have great effects on fretting fatigue life, the distribution of these parameters have been determined using Abaqus software for each contact type. The numerical simulations are quite consistent with the experimental results. The numerical results could reasonably explain the manner of variations observed in S–N curves for different contact geometries considered in this work.