Estimation of critical applied stress for crack initiation from a sharp V-notch

The aim of this paper is to estimate the critical applied stress value for a crack initiated from a sharp V-notch tip. The classical approach of linear elastic fracture mechanics (LELM) was generalized because the stress singularity exponent differs from 0.5 in the studied case. The value of the stress singularity exponent depends on the V-notch opening angle. The finite element method was used to determine the stress distribution near the sharp V-notch tip and for estimating the generalized stress intensity factor depending on the V-notch opening angle. The critical value of the generalized stress intensity factor was obtained using stability criteria based on the tangential stress component averaged over a critical distance from the V-notch tip and the generalized strain energy density factor. These criteria were applied in the case of corner stress singularity, as well. The calculated values of the critical applied stresses were compared with the experimental data from the literature, and the applicability of the LEFM concept is discussed.