Mixed-mode fatigue crack growth behavior of fully lower bainite steel

Fatigue tests were conducted on fully lower bainite steel, which is applicable to vehicle components due to its good resistance against crack propagation. The crack growth rates of this steel under mode-I and mixed-mode conditions were evaluated in terms of equivalent stress intensity factor range. The equivalent stress intensity factor range with growth rate results obtained under mode-I loading conditions can be used to predict the crack growth rate under mixed-mode loading conditions. Extended crack length rather than projected crack length is appropriate for the prediction of the crack growth rate under the mixed-mode loading conditions.