Stress intensities at notch singularities

In the context of linear elasticity, a stress singularity of the type K(n)r(delta) (delta < 0) may exist at re-entrant notch corners, with an intensity K-n. The magnitude of the intensity, referred to here as the notch stress intensity, characterizes the stress state in the region of the notch tip. We determined K-n for two mode I-type specimens that are proposed to characterize a critical value of K-n. Such a critical K-n may be appropriate as a failure criterion in situations where sharp re-entrant corners exist, and the region around the corner dominated by the singular field is large compared to intrinsic daw sizes, inelastic zones and process zone sizes. For these specimens we show that the region dominated by the singularity increases as the notch angle increases and is smallest for the limiting case of a crack. At the same time though, the strength of the stress singularity decreases with increasing notch angle. Estimates of the plastic zone size also decrease with increasing notch angles. For notch angles less than about 60 degrees, the stress singularity, stress intensity factor, region dominated by the singularity and the estimated plastic zone size do not differ substantially from those of a crack. (C) 1997 Elsevier Science Ltd.