Letter: The Submersible Failure

I'm going to offer an opinion regarding the catastrophic failure of the Titan submersible. It looks to me, from my mechanical engineering studies, like a buckling failure resulting from cyclic loading. Each trip to the depths subjected the vessel to extreme pressures that resulted in fractures that weakened it in vulnerable spots, leading to a rapid proceeding of a chain of events that destroyed the submersible nearly instantly when the submersible encountered those pressures again. I don't know how much this hypothesis has been investigated, but if it hasn't been, maybe some mechanical engineering student could investigate it and devise ways of predicting buckling failure under extreme pressures.