Fretting Fatigue Damage On The Toothed Mating Surface Of A Connecting Rod

Damages occur on the toothed mating surface of the connecting rod prematurely.Experiment and observation focusing on crack initiation and propagation areperformed on the toothed mating surface from fretting fatigue point of view. With themethod of contact finite element analysis (FEA) on toothed mating surface, numericalsimulation of stress field and displacement field is performed, and the crack locationsare predicted using Ruiz criterion. Finally, some measures to palliate fretting fatiguedamages are proposed. The following is accomplished:1. Damage statistic of crack locations for toothed mating surface is carried out.Further observation is performed on a typical sample to study the features offretting fatigue. Tests of material, including chemical composition, tensile testsand metallographic structure, demonstrate that connecting rod is free from defectsin material and provide data for FEA.2. Based on kinetic analysis, contact FEA on connecting rod under different workingstates is performed to evaluate the global stress/strain, then fine analysis usingsub-model on toothed mating surface is established to study the distribution ofstress and displacement fields.3. Accumulate Ruiz criterion is presented for crack prediction. According to dataobtained through FEA, FFDP on single working state is calculated, and thenAFFDP on a working cycle by weighting coefficient of each single state.Comparing with phenomena of short arm, it shows good agreement. Theprediction of long arm provides reference for improved design and damageassessment.4. Suggestions, including bolts pretension force, friction coefficient between matingface, optimal design and surface engineering, are made to palliate fretting fatiguedamages to toothed mating surface.