Research On Fretting Fatigue Life Prediction Of Dove-tailed Joint With Arc Contact Surface

Fretting damage widely occurs to the junction between two mechanical components. According to statistics, the damage of the dovetailed joints accounts for more than 17% of engine damage. So it is of great significance to do researches of fretting fatigue of the dovetailed joints in the engine. So research of fretting fatigue of the dovetailed joints in the engine compressor is carried out. The main content of this thesis includes the following several aspects.First, to deal with the fretting fatigue problem of the engine dovetailed joints, in this paper 56 fretting fatigue tests using two types of dovetailed join specimens are presented, one type has the arc to plane contact surface and the other adopts plane to plane contact style. The results show that the arc to plane contact style has a significant longer fatigue life than that of the plane to plane contact style. Among the arcs adopted, the ones with radius of 30 mm has the longest fretting fatigue life than those with radius of 50 mm and 100 mm.Second, based on the model of the damage potential energy proposed by Lemaitre and with the correction of the strain rate in the local fretting damage area, a prediction model is set up which is suitable for the fretting fatigue problem of the dovetailed joints. A prediction is made employing the model about the fretting fatigue life of the dovetailed joints which have contact surfaces of plane to plane and 3types of arc to plane. The results of prediction model show good agreement with experimental results.Finally, using the prediction model set up in this paper predicts the fretting fatigue life of the dovetailed joints with different radius. The results show that: among the arcs contact, the life is longer than the others when the radius is during 50mm~80mm.