Stress Intensity Factor for Elliptical Cracks

Hi, I just wanted some clarification with respect to a few equations relating stress intensity factor to semi-elliptical and quarter-elliptical cracks in solids.

The equations I have according to my notes are $K_{I_{(\varphi=\frac{\pi}{2})}}=1.12\frac{\sigma \sqrt{\pi a}}{\Phi}$ and $K_{I_{(\varphi=0)}}=1.12\frac{\sigma \sqrt{\pi \frac{a^{2}}{c}}}{\Phi}$

The problem is, from a diagram I have, it seems the first one is the quarter-elliptical (corner) crack and the latter is the edge. Is this correct? I am confused as it states the semi-elliptical crack first then the corner crack, though you would expect the explanations to be in the same order...

Here is the diagram btw.
[PLAIN]http://users.tpg.com.au/pbear88/files/123.png [Broken]

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Astronuc
Staff Emeritus
Hi, I just wanted some clarification with respect to a few equations relating stress intensity factor to semi-elliptical and quarter-elliptical cracks in solids.

. . . .

The problem is, from a diagram I have, it seems the first one is the quarter-elliptical (corner) crack and the latter is the edge. Is this correct? I am confused as it states the semi-elliptical crack first then the corner crack, though you would expect the explanations to be in the same order...

Here is the diagram btw.
. . . .