Effect Of Contact Pressure On Fretting Fatigue And Prediction Of Fretting Fatigue Life

Fretting fatigue lies in machine components widely, accelerates crack initiation and propagation, reduces greatly fatigue life, and may bring on catastrophic accidents.(1) According to the geometry configuration, contact condition and boundary condition of the fretting contact model, the finite element model of fretting damage model is set up. From this finite element analyses, the distributing of stress under contact zone are obtained, Based on ANSYS software, the calculation formula of contact stress of static fretting contact can be obtained.(2) The distribution of fretting contact stress is calculated. The calculation results indicate: with cyclic load increasing, the sticking zone reduce, but the sliding zone and the opening zone continuous increase , the relative sliding amplitude increase, crack initiate near inner edge of the fretted area location. With nominal contact pressure increasing, opening zone reduce; sticking zone increase; the sliding zone increase reduce after increasing; the relative sliding amplitude reduce; crack initiate near outer edge of the fretted area location.(3) The distribution of fretting contact stress of two kind of fretting bridge structure is calculated, comparing with NO.2 fretting bridge, opening zone and sticking zone of NO.1 fretting bridge is bigger; and the relative sliding amplitude is smaller; the crack initiate near outer edge of the fretted area location.(4) An estimating method of fretting fatigue life is presented based on nominal stress. The key of this method is the introducing of friction work, good agreement between the estimated result and experiment result, this indicate the method is available and effective.