Importance of Crack Tip Shape in Elastic-Plastic Fracture Analysis,

Elastic-plastic solutions for two crack problems are discussed. The problems involve blunt cracks. In one case, the crack tip geometry is semi-circular with parallel flanks in the other case, a circular tip geometry is considered. The authors refer to these as the U-tip and keyhole crack problems. The cracks have finite length and are within an infinite domain under plane strain constraint. Far from the crack a uniform tensile stress state is specified. The solution history to a remote stress level equal to 28 of the yield stress was obtained for each problem. Slipline analysis suggests that the near tip stress distribution for these cases and others such as the narrow ellipse and perfectly sharp crack are significantly different.