Hi Roland,
There was some work done by IBM [I think in Minneapolis] in the late 80's. I
showed that a full barrel crack needed to have at least a 90% physical
separation before a significant resistance increase could be measured. That is why
testing for barrel cracks is done in situ, or after the test a some elevated
temperature. At room temperature barrel cracks are essentially electrically
invisible; perhaps signal degradation could be found with high-frequency signals.

Werner

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