• A_A@lemmy.world
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    2 days ago

    … you’d need some massive …
    from the srticle :
    … a sphere nine metres in diameter and weighing 400 tonnes will be submerged …

    Can you calculate the weight of a sphere of 9 m of displaced water ?
    No ? Well, it is 382 tons.
    So, the concrete sphere is already massive by itself. “You” don’t need any complicated anchoring.
    Same goes with the rest of your mechanical engineering intuitions : you did not work in this domain or study it, did you 😆 ?
    Also, stress cycling is bad on most material, yes. But here it is compressive stress and the geometry is symmetric. Without further study, i want to believe this thing has good potential and my intuitions tells me it looks nice. Time will tell 😁 !

    • towerful@programming.dev
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      2 days ago

      Can you calculate the weight of a sphere of 9 m of displaced water ?
      No ? Well, it is 382 tons.

      Metric strikes again.
      I bet you didn’t even have to convert through football fields, elephants, or olympic sized swimming pools!

      • A_A@lemmy.world
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        2 days ago

        indeed i made a very simplified calculation not taking into account increase density of salted water nor increased density because of compressibility of water at 500 m deep. Basically i took 1m³(water) is 1 (metric) ton.

    • carl_dungeon@lemmy.world
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      2 days ago

      Thanks for the insight, I’m not a mechanical engineer, I’m a software engineer :) The walls on these spheres have got to be pretty thick- 400 tonnes is no joke. 3/4 of a meter if I had to guess.

      • A_A@lemmy.world
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        2 days ago

        Perfect guess ! (afaik) ρ(concrete) ≈ 2.5 tons/m³
        so full sphere ≈ (2.5 x 382) tons = 955 tons
        they have 400 t so the cavity removes :
        955 - 400 = 555 t … so 7.51m diam. cavity
        … so, yes 3/4m thick wall 😌👍 !

        • Cocodapuf@lemmy.world
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          1 day ago

          That’s exactly the way I would have calculated it, glad someone beat me to it though. Thanks!