A non-local approach based on the hypothesis of damage dissipation potential equivalence to the effect of stress gradient in fretting fatigue

A non-local approach based on continuum damage mechanics is proposed to take into account the stress gradient effect on fatigue crack initiation in fretting fatigue . The concept of subRVE (sub Representative Volume Element) is introduced as a smaller constituent unit of RVE (Representative Volume Element) and with the dimension of material average grain size for the purpose of considering the heterogeneous damage in the RVE. The fatigue damage in the subRVE is regarded as uniform, while the stress of subRVE is not uniform due to the effect of stress gradient. The fatigue damage evolution of each subRVE is derived by the hypothesis of damage dissipation potential equivalence with consideration of stress heterogeneity in the subRVE. Fretting fatigue is analyzed using this approach due to a zone of high stress gradient exists in the contact area. The predicted result from the proposed non-local model is better than that from local model by comparing with the experimental data. The interaction between wear and effect of stress gradient is also investigated.