HCF strength estimation of notched Ti–6Al–4V specimens considering the critical distance size effect

Generally not only the material but also the notch geometry affects the HCF strength. So, when evaluating the fatigue limit of notched Ti–6Al–4V specimens using the conventional theory of critical distance (TCD), a possible critical distance size effect was identified. In this paper, in order to overcome the critical distance size effect, Kt was introduced. And based on an assumption that the product of critical distance and Kt was constant, the TCD was modified to evaluate the HCF strength of notched Ti–6Al–4V specimens. The prediction results fell into an error interval of about ±15% using the modified TCD.