Titan testimony

The BBC is reporting on Lochridge's testimony about the Titan's implosion. The pictures are hair-raising--but lack explanation. Delamination as dramatic as that in the picture on the left would almost certainly have been spotted when the submersible was checked after a dive--and why would it delaminate so deep in the structure? What was the test they used that created that split?

The places of greatest stress, and greatest likelihood of water infiltration, would be where the composite met the endcap (or a penetration, but you get extra longitudinal compression from the endcap). I'd expect microscopic water infiltration at an edge flaw to cause the outer layer to delaminate (maybe with a little crackling noise?). That makes the composite structure just a tiny bit thinner there, and exposes the next layer to the water. Maybe there's a flaw handy; maybe not. But I (and apparently quite a few others) would expect material fatigue after a while, and the next layer's boundary with the endcap to slowly fribble.

The picture on the right screams for context. Is that supposed to be a typical layer? Do they pull regular test samples? (If not, why not?)

FWIW, when the leak broke through, the water speed would have been about 270m/sec--end to end in 24msec. A blink is about 100msec. Leaks are bad things