PSI - Issue 41

Liviu Daniel Pîrvulescu et al. / Procedia Structural Integrity 41 (2022) 492–499 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig 4. S-N fatigue curves for circular specimens = 6.2 and = 8.0 In the case of the two sets of test pieces tested under similar conditions (the first set of cast samples with a diameter = 6,2 and the second set with a diameter = 8,0 ) the equations of the fatigue curves are: , =6.2 = 394.58 ∙ ( ) −0.185 (2) , =8.0 = 38.665 ∙ ( ) −0.075 (3) The aim of the works is to determine the dimensional factor by the hypothesis of the correlation of the two fatigue curves obtained experimentally. For this we consider two fatigue curves A and B, Fig. 5 described by the following equations: , = ′ , ∙ ( ) (4) , = ′ , ∙ ( ) (5) First, it is considered that both fatigue curves have the same slope = = . For a finite life , the equations of the two fatigue curves (4) and (5) become: , = ′ , ∙ ( ) (6) , = ′ , ∙ ( ) (7)