The stress intensity factor of small cracks at notches

— It was found in a previous publication that stress fields around notches are quantitatively very similar, if the peak stress at the notch root (σpeak) and the notch root radius (ρ) are the same. As a consequence, small cracks (length l) should have the same stress intensity factor, if σpeak and ρ are similar. This implies that the geometry factor C in should primarily depend on l/ρ only, and not on other dimensions. Available data on calculated K values was analysed, which confirmed the similarity concept. An equation for C as a function of l/ρ was obtained. It was shown that K-values calculated with this equation are an accurate approximation for the stress intensity factor of small cracks at notches.