Multiaxial notch fatigue probability modeling based on three-parameter Weibull distribution and effective strain energy density

Multiaxial fatigue life analysis of notched specimens is a critical issue for structural integrity design. However, there is still a lack of multiaxial fatigue life prediction models with coupled notch effect and probability distributions, which are vital for the fatigue design of key components. Therefore, in this study, a new probabilistic fatigue life prediction model is proposed for notched specimens in structural integrity design, which combines the three-parameter Weibull distribution (TPWD) with the effective strain energy density (ESED) to estimate the fatigue life of notched specimens with different survival probabilities. Meanwhile, the study involves the numerical calculation of the critical plane, extraction of the stress–strain distribution, calculation of strain energy density (SED), determination of critical damage region (CDR), and introduction of a weight function to quantify the damage weights of stress–strain at different locations around the notch on the effective damage parameters of the notch. The proposed model and three other energy-based models are validated using experimental data from notched specimens of Al7050, GH4196 alloys and medium steel En8, and the comparison results exhibit that the proposed model yields higher accuracy than three other models within the ± 3 life factor. Meanwhile, P-Weff-Nf curves of notched specimens with different survival probabilities are presented and analyzed under multiaxial loading. Overall, the proposed approach provides a new way to estimate the fatigue life of notched specimens, which can be useful for the fatigue design of key components.