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Old 09-05-2017, 12:58 PM   #7
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: [Spaceships] Passage Tubes? Stats? Cost?

Weight actually scales in part with volume, that is probably not very interesting on the scale of a passage tube.

In general, the force trying to split apart a circular tube is (tube radius) * (pressure within tube) * (distance over which you are measuring) -- i.e. if the tube is at 0.2 bar (about right for pure oxygen) and a 1m radius, the force trying to split the tube walls is 20,000N/m. If the tube walls have a strength of 200MPa, they need to be 0.1mm thick, and the total wall volume is 6.3e-4m^3/m; assigning a convenient density of 1600kg/m^3, that's about 1 kg/m, or 27 kg (about 60 lb) for the entire tube. This can be adjusted somewhat based on materials and desired safety margin.

Note that it can't be collapsed unless the air is drained from it. Based on my experience with collapsing tubes, it's probably around 5% volume when collapsed.
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