Fatigue life estimation for multiaxial low-cycle fatigue regime: The influence of the effective Poisson ratio value

A critical-plane criterion for multiaxial fatigue regimes characterised by low number of stress cycles is discussed. Such a criterion is formulated in terms of strains, by obtaining the displacement components acting on the critical plane from the strain tensor and, then, by considering an equivalent strain as a parameter to quantify the fatigue damage. Since the metallic materials generally behave in a plastic manner in low-cycle regime, the effective Poisson ratio has to be taken into account when defining the strain tensor. The theoretical results are here determined by varying the value of such a parameter in order to assess its influence on the fatigue life estimation. The effectiveness of the criterion is evaluated through experimental data related to fatigue tests on metallic hollow specimens under biaxial fatigue.