you remember the last post i made in this community about farming on mars in small greenhouses?
yeah, that rings a bell. i just wanted to know how to construct these plastic tubes sothat they would hold 1 bar of pressure inside. so i did some calculations. they are a real mess, don't look at them:
(r/d is the ratio of the tube radius to the wall thickness btw. r/d = 300 is the point where it tears, so having a thicker wall than that should be fine)
i mostly wrote this down as a reminder for myself sothat i can roughly understand what i did later.
anyways, the results are: basically you can make such a tube with 10cm diameter easily out of polyethylene or any other type of polymer with only a wall strength of 1mm. it will hold, it won't burst. i used some insights from ultimate tensile strength, linear elasticity (Young's modulus) etc.
basically what i did is to assume that the force that the wall material exerts to push to the inside is equal to the gradient in spring-energy that would be stored inside the wall material depending on radius. So dW(r)/dr = F is the force with which the wall material pushes inward, where W(r) is the mechanical stress energy stored in a slice of the tube of 1mm thickness.
ask if you want to know something. i'm tired rn and can't tell what i might have missed.
