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Recent content by Alatza

  1. Alatza

    Thin-walled cylinder under pressure

    TGS4, I'm in Brazil. I will check the regulations here on this subject. BigInch, I will check this question further. After reading your comment I also remember that there will be some load supported vertically by the cylinder. There will be a thick aluminum disk and this weight certainly will...
  2. Alatza

    Thin-walled cylinder under pressure

    TGS4, This one? https://www.asme.org/products/codes-standards/bpvcviii1-2015-bpvc-section-viiirules To be honest, the problem is the price. I don't have $660 to invest on this part of my project since I still have to pay for the glass, vacuum pump, aluminum parts, etc... :( But probably it...
  3. Alatza

    Thin-walled cylinder under pressure

    Good point! But by what I read so far the longitudinal stress is half the hoop stress. So thickness calculated for hoop will cover longitudinal as well.
  4. Alatza

    Thin-walled cylinder under pressure

    TGS4, thanks! This explains a lot, indeed. Guys, I found new references. Both uses the same method (NOT Von Mises since glass is a brittle material and NOT stress since the collapse is due to buckling) - Process Equipment Design - Lloyd E. Brownell, Edwin H. Young. John Wiley & Sons, Inc...
  5. Alatza

    Thin-walled cylinder under pressure

    BigInch, Thanks again for your help. That formula would only account for radial stress caused by internal and external pressure. Are redial stresses the only stresses here? The axial stress formula is p*r/ 2t, so the hoop stress is bigger. How is this tube being supported? Are there any...
  6. Alatza

    Thin-walled cylinder under pressure

    BigInch, thank you! You are right. So I have to use another method. Von Mises is not applicable to glass. Most books I found so far shows the stress in thin-walled cylinder as: s = p * r / t s = stress p = pressure r = cylinder radius t = wall thickness They say the formula is the same for...
  7. Alatza

    Thin-walled cylinder under pressure

    LittleInch, Thank you, man! I tried your advice on using the paper's data as input and found my mistake (Excel should not be used for this). Now I got 1.2 mm as the minimum thickness for 10-3 Pa. So I intend to use 5 or 6 mm. What makes sense now. mbt22, Sorry, I didn't get why Von Mises...
  8. Alatza

    Thin-walled cylinder under pressure

    Hello everyone! I am designing a glass vacuum chamber to work with 0.001 Pa for a sputter coater. The method I found is Von Mises equation for thin-walled cylinder buckling. More precisely, I am following this paper: "Prediction of vacuum-induced buckling pressures of thin-walled cylinders"...

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