[PSUBS-MAILIST] Titan submersible missing at Titanic site

[Sean T. Stevenson via Personal_Submersibles]

I was just going to mention that. To say nothing of the appropriateness of FRC in submerged cyclic service generally, the composite hull on Titan was wound in the principal hoop stress direction only. A more appropriate layup would have incorporated longitudinal and/or +/- 45° layers as well. Unless you are floating the cylinder between mechanically constrained end seals (i.e. with the end caps connected via tie rods that carry the compressive stress), you will never have pure hoop stress in the cylinder wall.

I'm less sold on longitudinal collapse as the failure mode, as opposed to overall buckling. FRCs have their own specific failure modes which can include delamination, loss of bond between matrix and fiber, shear of the fiber, matrix creep, and certain dislocation effects. Though a longitudinal instability or initial localized failure of the hull due to longitudinal stress could easily have precipitated an overall buckling event, I expect that the general deformation mode will be determined to have been radial collapse vs an accordion-type buckle.

Sean
-------- Original Message --------
On Jun. 29, 2023, 09:47, MerlinSub at t-online.de via Personal_Submersibles wrote:

> I have seen a video how they make the carbon cylinder and can imagine that the boat imploded in longitudinal direction.
>
> Create a massive shock wave with push the window out (not in). As I saw in another video the window was hold by only 4 bolts outside.
>
> All titan parts in the video seems undamaged.
>
> Carsten
>
> -----Original-Nachricht-----
>
> Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site
>
> Datum: 2023-06-29T17:27:48+0200
>
> Von: "Jon Wallace via Personal_Submersibles" <personal_submersibles at psubs.org>
>
> An: "personal_submersibles at psubs.org" <personal_submersibles at psubs.org>, "personal_submersibles-request at psubs.org" <personal_submersibles-request at psubs.org>
>
> Interesting that at 1:01 the viewport is obviously not in place. I would have thought that for this kind of post accident analysis they would leave everything intact and as found. I have to wonder if the viewport was removed to allow the crane strap to get a firm grip on the tank head or if that was just a convenience because the viewport blew out.
>
> Jon
>
> On Wednesday, June 28, 2023 at 07:19:51 PM EDT, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> [Raw video: Wreckage from implosion of Titanic-bound sub arrives in Canada](https://www.youtube.com/watch?v=458KFQXJ_Zs)
>
> Raw video: Wreckage from implosion of Titanic-bound sub arrives in Canada
>
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