Titan Submersible Vessel

[sugar magnolia]

I guess that answers the question about which is better suited, carbon fiber or titanium.

[RTH10260]

Titanic tourist sub photos show wreckage being brought ashore

https://www.bbc.com/news/world-us-canad ... gn=KARANGA

Interesting that the port hole glass is missing. Maybe it did blow out when water endered the cylinder. Or it may have broken and be the origin of the accident. They must have been using the submersible roboter that inspected the Titanic to look for the remains of its lesser cousin.

[RTH10260]

Report by The Guardian on parts recovery:

Titan submersible debris returned to land after fatal implosion
Pieces of mangled craft brought ashore in Newfoundland after five killed on voyage to Titanic wreck

Guardian staff and agency
Wed 28 Jun 2023 18.03 BST

https://www.theguardian.com/world/2023/ ... -oceangate

[Kriselda Gray]

The mother of the teen who died seems to have changed her story a bit:

The mother of the teenager who died on the Titan submersible has said she gave up her place to her son “because he really wanted to go”.

Suleman Dawood, 19, and his father Shahzada, 48, were among five people who died when the vessel imploded on a journey to view the wreck of the Titanic.

Christine Dawood told the BBC the original trip had been scheduled before the pandemic and said her son had been disappointed that he was not old enough to accompany them.

She said: “It was supposed to be Shahzada and I going down. I stepped back and gave the place to Suleman because he really wanted to go.”

Asked how she felt about the decision, she replied: “Let’s just skip that.”

https://www.theguardian.com/world/2023/ ... ace-to-son

[chancery]

From the descriptions of the immensity of the forces involved in an implosion at 13,000 feet beneath the surface, I'm surprised that such large intact pieces were found. There was talk of the force being large enough to generate plasma.

However, I guess that thick pieces of titanium are pretty strong, and there was nothing for them to crush against. Of course, IANAEng. I'd be interested to hear comments from people with technical knowledge.

I was skeptical about the social value of keeping expensive equipment mobilized to search for wreckage, since there is no chance of finding remains. There also seems to be sufficient information available on dry land from which to draw conclusions about whether the Titan's design was a good one.

However, since some pieces have been recovered, I guess that it will be worthwhile to study them.

[AndyinPA]

And, in this particular case, they really need to study the actual pieces, I would think.

[roadscholar]

The Onion strikes again!

Critics Say Submersible Should’ve Been Tested With Poorer Passengers First

WASHINGTON—Analyzing the mistakes OceanGate made that led to the vessel’s disappearance, critics told reporters Thursday that the submersible should have been tested with poorer passengers first. “The company skipped the very crucial step of sending five lower-class people to the bottom of the ocean to make sure it was safe enough for the wealthy,” said Otto Scofield, a member of the Marine Technology Society, adding that no one with a net worth above $50,000 should have been in the submersible. “OceanGate made the mistake of not using minimum wage workers and unemployed people on government welfare programs to test the seaworthiness of the craft, which was not billionaire-ready. Running more trials with some homeless people would have made all the difference, and the deaths of several wealthy people could have been prevented.” Scofield continued that using children of color from impoverished families would have been ideal as more would have been able to fit inside the submersible.

https://www.theonion.com/critics-say-su ... 1850566314

Quite a modest proposal.

[RVInit]

ABC news reported they also found “presumed “ human remains.

[chancery]

Quite a modest proposal.

[keith]

ABC news reported they also found “presumed “ human remains.

I personally find that hard to believe. What could possibly remain? A couple of teeth?

[RVInit]

ABC news reported they also found “presumed “ human remains.

I personally find that hard to believe. What could possibly remain? A couple of teeth?

If the are “presuming” that’s what it is, must not be much.

[much ado]

I would guess large bone fragments.

[RVInit]

I would guess large bone fragments.

That sounds reasonable. CNN reported that "US medical professionals" will be examining those remains.

[AndyinPA]

Or not so large; they can get DNA out of either.

[Slim Cognito]

From the descriptions of the immensity of the forces involved in an implosion at 13,000 feet beneath the surface, I'm surprised that such large intact pieces were found. There was talk of the force being large enough to generate plasma.

However, I guess that thick pieces of titanium are pretty strong, and there was nothing for them to crush against. Of course, IANAEng. I'd be interested to hear comments from people with technical knowledge.

I was skeptical about the social value of keeping expensive equipment mobilized to search for wreckage, since there is no chance of finding remains. There also seems to be sufficient information available on dry land from which to draw conclusions about whether the Titan's design was a good one.

However, since some pieces have been recovered, I guess that it will be worthwhile to study them.

Narrator: It's not.

[neonzx]

WHY do they need DNA? They think the remains are some other persons who got squashed in that death trap?

[much ado]

WHY do they need DNA? They think the remains are some other persons who got squashed in that death trap?

They need to sort out the remains into boxes to give to the next of kin for proper burial. That's all.

[somerset]

From the descriptions of the immensity of the forces involved in an implosion at 13,000 feet beneath the surface, I'm surprised that such large intact pieces were found. There was talk of the force being large enough to generate plasma.

However, I guess that thick pieces of titanium are pretty strong, and there was nothing for them to crush against. Of course, IANAEng. I'd be interested to hear comments from people with technical knowledge.

Titanium is also somewhat malleable*, so it can flex a bit when stressed before it fractures. Assuming the carbon fiber tube fractured and fragmented, the Ti end caps would probably be distorted, but relatively intact

*Correction. Pure titanium is brittle at room temperature and below. It's very ductile and fairly malleable at higher temperatures. These properties vary considerably in different titanium alloys, and it's likely the end caps aren't pure titanium.

I was skeptical about the social value of keeping expensive equipment mobilized to search for wreckage, since there is no chance of finding remains. There also seems to be sufficient information available on dry land from which to draw conclusions about whether the Titan's design was a good one.

However, since some pieces have been recovered, I guess that it will be worthwhile to study them.

I think you were right to be skeptical, but I also think the additional cost of keeping these deployed assets on site for an extra day or two to collect samples isn't that high. I'd expect the initial cost of deploying the assets was the greatest expense.

I'm not an expert in composite materials failure analysis (mine is in FA of electron and photonic devices), but I don't expect there's much to learn from the fragments of the carbon fiber tube. I think it's highly likely it started to delaminate after multiple dives, and even if a bubble or other defect initiated the failure on this dive, it would have almost certainly failed in the not too distant future. I don't think there's much to be learned or improved from doing an FA on the fragments and the Ti end caps, but if an ROV is already on-site, it might as well collect the samples while it has the opportunity.

[sugar magnolia]

WHY do they need DNA? They think the remains are some other persons who got squashed in that death trap?

The same reason they did DNA analysis on the victims of the Twin Towers for years.

[John Thomas8]

[Sam the Centipede]

Quite a modest proposal.

And a "well-played sir!" from me too!

[Sam the Centipede]

I'm not an expert in composite materials failure analysis (mine is in FA of electron and photonic devices), but I don't expect there's much to learn from the fragments of the carbon fiber tube. I think it's highly likely it started to delaminate after multiple dives, and even if a bubble or other defect initiated the failure on this dive, it would have almost certainly failed in the not too distant future. I don't think there's much to be learned or improved from doing an FA on the fragments and the Ti end caps, but if an ROV is already on-site, it might as well collect the samples while it has the opportunity.

I'm no expert either, not even close - about 20-25 years ago I made fracture mechanics and fatigue calculations on carbon fiber reinforcement of flanges of old iron (yes, not steel) beams using finite element analysis and J-integral calculations but I can't remember anything interesting from that exercise without digging out the report. I too would be suspicious of the carbon fiber before the titanium, especially for low cycle failure (which this was).

And yes, with the gear already present on site, it was prudent to retrieve samples at relatively little expense. Whether one cares much of little about this specific incident it is a fact that engineering learns massively from its mistakes. That knowledge will feed into future projects, even if the knowledge is only "no, don't do that, it's a really bad idea".

[John Thomas8]

One of the reasons F1 race cars are so expensive is because of the amount of carbon fiber parts they have to replace. They don't last multiple races because their short life span.

[RTH10260]

I'm not an expert in composite materials failure analysis (mine is in FA of electron and photonic devices), but I don't expect there's much to learn from the fragments of the carbon fiber tube. I think it's highly likely it started to delaminate after multiple dives, and even if a bubble or other defect initiated the failure on this dive, it would have almost certainly failed in the not too distant future. I don't think there's much to be learned or improved from doing an FA on the fragments and the Ti end caps, but if an ROV is already on-site, it might as well collect the samples while it has the opportunity.

I think there will be a forensic analysis done, there have been reports that the hull was made even thinner than specfied, and that was reportedly also less than engineers recommended.

[andersweinstein]

Terrific (and very damning) piece. Lot of original reporting on folks warning of disaster and how their concerns were suppressed: