Change in stress intensity factors

Hi everybody,

Is there any limits for using of LEFM?  I have modelled a beam with a penetration.I have moved the holes vertically in the beam and obtained the stress intensities for each movements at the corners of the hole. Now the hole is closing the edge, stress intensities in mode I and II, suddenly change values (positive to negative and vice versa)  what does this mean ?... Does it mean that I should limit my movements?,,,,

Thank you,

Parisa,