The expressions of stress-strain field in a finite plate with crack-tips of different radii of curvature have been derived by the method of conformal mapping-weighted residues. The stress-strain field has been evaluated for the LYIZM piate of dimensions 300 mm x 150 mm x 2 mm under uniaxial tension. Values of (I, computed by the present method and by Creager's formula are in agreement within 5% in the distance range of (x -a)/a Q l/50 from the crack-tip. The radius of curvature of the crack-tip has a significant effect on the stress cv at the tip. While it has little effect on the stress uz and almost no effect on the stress Us in the elastic region, it has a remarkable effect in the plastic region for small-scale yielding and very little effect for large-scale yielding. The effect of the radius of curvature (for p < 2L/250) on the stress intensity factor at the crack-tip is negligible.
Uniaxial tensile tests on 3OOmm x 150mm x 2 mm specimens of LYlZ-M with crack-tips of different radii of curvature have been performed, and strain measurements made by Moire's method and electrical-resistance gauges. Experimental results show that the radius of curvature has no effect on the strain cy in the elastic region; measured values of cx and ey in front of the crack from the boundary of the plastic region to the edge of the specimen agree with the computed values to an accuracy of 5%; the measured values of K, from specimens with cracks of different radii of curvature @ d 2L/250) are consistent with the computed values.