Research on fretting fatigue life estimation model considering plastic effect

The contact surface between the aero-engine turbine blade and the disk dovetail junction structure is small, which results in severe fretting fatigue. The fretting fatigue of the structure is sharply aggravated by the plastic effect under the action of alternating loads. The existing fatigue life estimation model may need to be improved in considering fretting and plastic effects, making the result greatly differ from those found in practice. Accordingly, this work intends to propose a fretting fatigue life estimation model based on plastic effects and standard surface-to-surface contact theory. The distribution of both the equivalent and contact stresses found in the contact area was analyzed using finite elements. The aim was to determine the fatigue critical point of the structure. The maximum cyclic load stress value was obtained through the fretting fatigue experiments to verify the model accuracy. The model applicability was verified and analyzed using dovetail experiments. The experimental results have shown that the error between the values obtained using the proposed estimation model and experiment is below 12%, meaning that the accuracy is high. Therefore, the estimation model is suitable for estimation the dovetail structure fretting fatigue life. This paper provides theoretical support for the design of the dovetail tenon structure. The contact surface between the aero-engine turbine blade and the dovetail junction structure is small, which results in severe fretting fatigue. The fretting fatigue of the structure is sharply aggravated by the plastic effect under the action of alternating loads. The existing fatigue life estimation model may need to be improved in considering fretting and plastic effects, making the result greatly differ from those found in practice. Accordingly, this work intends to propose a fretting fatigue life estimation model based on plastic effects and standard surface-to-surface contact theory. The finite element analysis is used to analyze the distribution of equivalent stress and contact stress in the contact area, in order to determine the fatigue risk point of the structure. The accuracy of the model is verified by obtaining the maximum cyclic load stress value through the fretting fatigue experiment. The universal applicability of the model is verified through the dovetail experiment analysis. The experimental results show that the error between the theory and experiment of the proposed estimation model is below 12%. Therefore, it is suitable for the estimation of the fretting fatigue life of the dovetail structure.