Fatigue strength under combined bending and torsion proportional loading of bronze specimens with and without geometric notch

The paper presents the results of fatigue life testing on RG7 bronze specimens, both with and without notches, under various loading conditions. The determined fatigue characteristics of the analysed material were used to determine the impact of notch operation on fatigue life under cyclic loading conditions. From the analysis of the results obtained, it can be seen that all fatigue notch factors proposed in the literature for all analysed cases are overestimated, at least for RG7 bronze. The closest to the fatigue notch factor is the Peterson model. However, this parameter also approaches the real one only for gigacycles. A more detailed analysis shows that only the DuDe model reflects a lower notch action factor for shorter durability, as results from the characteristics determined for individual tests. It was proposed that the fatigue performance factors of the notch be reduced by a factor depending on Poisson's ratio. The analysis was supplemented with the topography of fatigue cracks in selected fractures.