CEO said Titan’s hull made with carbon fiber that was past airplane shelf life | Hacker News Reader

CEO said Titan’s hull made with carbon fiber that was past airplane shelf life

insider.com

8 pointsrussfink10 comments

Prepreg carbon fiber is infused with epoxy resin by the carbon fiber textile manufacture, and heat cured after it is formed into the necessary shape.

It has to be refrigerated to slow down the resin curing to give it a usable shelf life.

The accusation in the article seems to be of the form that expired or rapidly approaching EOL material was used in the fabrication process, (likely tailings or castoff from other processes). I just can't see a business (Spencer Composites) taking the reputational risk of "hey, I got a pile of Quality rejected carbon fiber originally slotted for Boeing that's perfectly good for "insanely more dangerous specifications here*. Give it to you for a discount.

I could see OceanGate sourcing something like that and obscuring the provenance from Spencer Composites though. The irony in all this, of course, is that if this were built to SUBSAFE quality standards, we'd know exactly the provenance of these materials, as tracing this sort of thing is one of the goals of such a Quality Assurance Program.

In the end though, the carbon fiber was laid, it just was not tested with industry standard methods due to the exceptional thickness of the end product. I'd be curious to know what the testing challenges would actually have entailed.

Based off a quick perusal of

https://en.m.wikipedia.org/wiki/Carbon_fiber_testing

Looks like Ultrasound would have been right out. X-ray and Thermography would still have been viable-ish. Would have to do more reading.

I imagine that companies like Spencer Composite produce a lot of parts to spec without knowledge of what they are for.

Like I said, don't know the business vertical very well. That may very well be the case, and I'm not hot to trot put that much onus on them to keep a customer from doing something stupid.

Conclusion: Business leaders make lousy engineers.

They refuse to defer to others. They can't resist enforcing their judgment even in situations where their expertise is lacking. And never mind the fact that business concerns often conflict with safety which calls their judgment into question.

This is essentially what happened with the Boeing 737 Max and it is what happened here too. In both cases, repeated warnings were ignored, overruled and dismissed by business leaders with minimal engineering experience and people died --- as a result of arrogance.

Safety is only "pure waste" when your main focus is sales and marketing and your judgment is compromised.

A different article [0] brought up the possibility of fatigue from repeated dives; any thoughts from folks involved in engineering, composites manufacturing, or testing?

[0] https://abcnews.go.com/amp/US/wireStory/scrutiny-rises-titan...

TIL carbon fiber has a shelf life

It's not the carbon fiber, its the resins. Some carbon fiber products have the resin applied when the final product is made, others have it pre-impregnated by the fiber manufacture. Prepreg fibers have to be used before the resins go bad.

I never heard of pre-impregnated fiber... Is it kept in a vacuum seal before getting formed?

No, it doesn't air cure. It is refrigerated to slow the reaction between causing it to cure.

It is formed and heated under pressure to cure. This is typically done in an autoclave.

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