Stress Intensity Factors Evaluated from Discontinuous Displacements along a Slant Crack with a Center-Hole Notch.

Abstract

For cracks with a center-hole notch under the mixed-mode condition, a method is proposed in which the stress intensity factor can be directly evaluated from the discontinuous crack displacement, thus representing effective stress intensity factors. Using this method, the effect of crack surface roughness on the stress intensity factors KI (mode I) and KII (mode II) was discussed especially in relation to the crack surface contact of the slant-annealed crack under tensile loading, where crack opening (or closing) was estimated to be induced gradually during loading (or unloading). Also, it was found that the residual plastic layer in the wake of the fatigue propagation crack reduced the stress intensity factors KI and KII determined from the discontinuous displacement along the slant crack with a center-hole notch under tensile loading.