Prediction Method On Fretting Fatigue Life Of Dovetail Joint

Fretting damage is one of the most common damage in engineering. It occurs at the contact surface where exist relative micro-slip less than 300μm and vertical pressure between two components. It usually makes the initiation and growth of the crack rapidly at the contact area, reduces the fatigue strength and even causes security accidents. Many failures of dovetail joint in aero-engine are found under fretting fatigue circumstance. At present, the major work are focused on the fretting damage mechanism. It's important to research fretting fatigue life prediction of the dovetail joint.In this thesis, firstly some mainly fretting fatigue damage mechanisms were introduced, and it was gotten that the fretting experiment life of the dovetail joint according the S-N curve of the fretting fatigue experiments. The finite element model of dovetail joint was created by ANSYS software, and the stress field of the contact surface was gotten. The local important fretting fatigue parameters were analyzed, and the SWT parameter was used to predict the position of crack initiation at the contact surface, the result was concide with the experiment. Then, the fretting fatigue life prediction model was gotten according the experiment data, and it was used to predict the low cycle fretting fatigue life of the dovetail joint, the error was acceptable and the result was reasonable and effective. At last, the effects of the coefficient of friction and the bottom angle,θwere analyzed in order to protect the fretting damage. In engineering, the fretting damage can be reduced by reducing the coefficient of friction and choosing 40 ~45 of the bottom angle.