New energy model for fatigue life determination under multiaxial loading with different mean values

Fatigue life estimation for 2017A-T4 and 6082-T6 aluminium alloys subjected to bending-torsion with mean stress

“…During the experimental tests of the 2017(A)-T4 aluminium alloy [5,30,31], the effect of mean torsion stress on fatigue life was discovered. It must be noted that not all materials exhibit sensitivity to the mean torsion stress (e.g.…”

“…It must be noted that not all materials exhibit sensitivity to the mean torsion stress (e.g. 30NCD16 steel) [31].…”

“…The new fatigue life estimation model is based on the criterion by Łagoda and Macha [4,7,[30][31][32]. The equivalent stress is a linear combination of normal and shear stresses and takes up the form: r a;eq ¼ Bðs gs;a þ s gs;m Þ þ Kðr g;a þ r g;m Þ; ð1Þ where r g,a -normal stress amplitude to the critical plane: r g;a ¼ r a cos a 2 þ s a sin 2a;…”

“…By analysing the stress condition for pure torsion and pure bending at constant-amplitude load conditions, a relationship is formulated which describes important factors for the combination of individual components. The coefficients can be presented as follows [30][31][32]:…”

Fatigue life estimation for selected materials in multiaxial stress states with mean stress

“…Usefulness of the model was verifiedby comparing calculation fatigue life and experimental test results of 2017A-T4 and 6082-T6 aluminium alloys (Kluger and Łagoda, 2014;Niesłony et al, 2014), S355J0 alloy steel (Pawliczek, 2000) and Ti-6Al-4V titanium alloy (Krgo et al, 2000;Kallmyer et al, 2001) for which sensitivity to mean torsion stress was discovered. The proposed model is very satisfactory in terms of calculation time.…”