Comments by "alafrosty" (@alafrosty) on "Solar Eclipse Timer" channel.

  1. When you don't have a known manufacturing process, you don't have a safety factor at all as you have no idea about how strong the one off component actually is.
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  2. I think SR just decided that if things worked once, then that was proof they would continue to work. He didn't understand much, especially repetitive stresses.
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  3. Disagree! CF is the wrong material for almost all compression critical structures. It is great in tension as you point out.
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  4. ​@ABaumstumpf CF strength under compression is far more related to the matrix bulk than the CF. It's fundamentally the wrong material for the job. Should have used a steel or titanium alloy. SR should not have had any roll in making engineering decisions. He was a terrible engineer and a worse manager.
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  5. I think you are giving OG too much credit by accusing them of designing anything.
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  6.  @grnbrg  that thing wasn't "cutting edge;" it was brazenly ignorant of engineering principles.
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  7. Yes on end caps, however this point is another way the sub could have failed due to terrible engineering design and manufacturing choices. It is an example of how craven capitalism drove not an isolated mistake, but a wholesale abandonment of design safety considerations.
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  8. Nope. Design failed elsewhere first, but this problem was next on the list of examples of why some people should not be allowed to make design decisions.
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  9. Craven capitalism and hubris.
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  10. ​ @luipaardprint have you ever tried to use rope in compression? Same deal as CF. Go back to your strength of materials class because you evidently didn't get it the first time.
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  11. @thomasparthenay1791  weight was unimportant for the sub's purpose - it was taking on ballast, so using heavier materials would actually be advantageous from multiple factors.
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  12. Yes, and the hull was in tension, not compression. Which is why CF was a terriblecdesign choice for a manned chamber.
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  13. Honestly, you might be better with zero hours and a willingness to defer to actual design experts, and not overrule safety considerations because they are costly.
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  14. Systematic ignorance of human safety praying at the capitalist altar.
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  15. They could have vacuum bagged it, but that would've been spendy
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  16.  @PeterCoupland  and the 4.5" was selected as a dimension to allow the previous cap ring to be used rather than any sort of "calculated" dimension.
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  17. @ammerudgrenda  if the structure was in tension, the 45s would absolutely create load paths, but not under compression with any significant manner. Kinda like how concrete is really weak in tension. I took engineering classes in strength of materials; FEA; and composites.
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  18. The wrinkles were created by voids. Sanding exposed the voids but cut through the CF. The CF in compression was terrible to begin with, but chopping through it was worse.
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  19. @ctrlaltdebug  sanding the voids down was cosmetic to make the hull not look like a complete toad. So many actual submariners told SR the design was terrible and not certifiable.
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  20. Iron not included
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  21. Voids in the underlying matrix. One of the pix in the vid depicts them.
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  22. Moot because CF not really contributing in compression. The problem they were trying to address was large voids in the matrix, while ignoring the myriad small voids that remained. So much dumb!
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  23. @solareclipsetimer  under compression, the fibres just fold in the matrix. They could've used a prepreg full weave fabric and it wouldn't have made any important difference.
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  24. I'm not completely sure that is true, but we have proven isotropic materials for the task, so stick with them!
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  25. ​ @thomasparthenay1791 no, aluminum would have been a terrible choice for SO many reasons. You need to take a strength of materials class.
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  26. They could have added more matrix and flattened that to get it flat, but that still would have left voids in the CFRP that weakened the hull.
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  27. Stated perfectly.
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  28. That was a bad example. In the OG sub, all walls were in compression with no tension. In a bridge, half deck/truss is compression and half is tension. Not really comparable.
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  29.  @YsimulAC  the only way you might see hull necking is in an axial slice, not a radial slice. The maximum inward deflection would be toward the midship, but the entire stress loading will be compressive whereas loading a bridge (not using pre-stressed concrete) gives you tension on the bottom and compression on the top of the structure. Ultimately, the vessel failed at the join between the composite hull and the end ring. Whether that was too much flex or not enough adhesive or the composite let go under bending stress, we will never know. Any way you look at it, CF is the wrong material for a deep sea sub that needs to hold air. The ends of ideal bridges usually end abruptly at a wall or pivot. In the sub, the ends attached to an overlapped joint ring with different moduluses than the CF, so pretty unusual and depth-dependent end loading.
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  30. There was only one V2 hull.
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  31. High school science project taught by the gym teacher.
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