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Stress Intensity Factor for Elliptical Cracks

  1. Nov 5, 2011 #1
    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 [itex]K_{I_{(\varphi=\frac{\pi}{2})}}=1.12\frac{\sigma \sqrt{\pi a}}{\Phi}[/itex] and [itex]K_{I_{(\varphi=0)}}=1.12\frac{\sigma \sqrt{\pi \frac{a^{2}}{c}}}{\Phi}[/itex]

    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]

    Thanks in advance!
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Nov 5, 2011 #2


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    The diagram is of a semi-elliptical crack. The two expressions are for different locations on the root, and they are of the same order (assuming I'm understanding your comment/question).

    a is the same order as a2/c
  4. Nov 5, 2011 #3
    Hi, thanks for the reply, cleared everything right up for me.

    Guess this can be closed now.
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