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  1. pdiculous963

    reference/textbook for theory behind VIII-1 impact testing exemptions

    The background to the VIII-1 rules is documented in Annex A of WRC Bulletin 528. They were originally developed by Corten using a fracture mechanics basis. On your question, toughness is not actually a material property as it can vary based on thickness. Thick components tend to have higher...
  2. pdiculous963

    MAWP vs DP for calculating minimum required thickness

    Often manufacturer's will stamp vessels for the highest calculated MAWP, not the design pressure. What is the relief device set pressure on the vessel? If it is at the design pressure, it may be acceptable to use that to calculate tmin, else the MAWP should be used. If you do base it off the...
  3. pdiculous963

    PTB-4-2013 Eample E4.3.7 mystery variables

    As the Code applies to a wide range of vessels with unlimited loading scenarios, the Code does not define Fs and Ms. The designer is expected to use engineering principles to determine the unit forces f1 and f2. The author of the document arbitrarily used Fs and Ms to designate axial force and...
  4. pdiculous963

    PTB-4-2013 Eample E4.3.7 mystery variables

    This is simply a strength of materials calculation. As noted in the Code f2 is the axial load per unit width of circumference. The axial load is a combination of the axial force and the bending moment. The first half of the equation is converting the force into force per unit width by...
  5. pdiculous963

    How to detremine the Adjusted MDMT for auto-refrigeration condition

    I would limit the adjusted MDMT to -155.
  6. pdiculous963

    Modelling frost heave and tank settlement in Caesar

    I would imagine you can use CNODES to move the restraints themselves. Common way to move supports based on thermal expansion.
  7. pdiculous963

    Div 1, Code Case 2695

    MrPDes - The shell will have a slightly different thickness for Div. 1 or Div. 2 as the Div. 2 equation is a limit state equation based on maximum shear stress theory. This equation explicitly considers radial stress, whereas the Div. 1 equation is simply hoop stress equation with a lame...
  8. pdiculous963

    Div 1, Code Case 2695

    Paragraph (f) of the Code case prohibits the use of Part 5, so you are out of luck on using FEA on the nozzle with a ratio over 1.5. You probably will not get a lot of benefit using CC2286 it on the shell. You'll get the most benefits on formed heads, cone to cylinder junctions, and nozzles...
  9. pdiculous963

    Div 1, Code Case 2695

    TGS4 - The way the Code case is written is that if you design the shell using the Part 4 rules, then you have to design the nozzles in accordance with Part 4, but not the other way around. Take a look at paragraph (d)(1) of the Code case. The Code case doesn't appear to restrict you from using...
  10. pdiculous963

    Div 1, Code Case 2695

    It is understood that Div. 1 does not have this limitation, but the Div. 2 rules are different from the Div. 1 rules and therefore have different limitations. This ratio limit of 1.5 is intended to ensure that the rules in 4.5 are accurate/appropriate. Since Div. 1 uses different rules, this...
  11. pdiculous963

    Div 1, Code Case 2695

    You need to comply with all the rules of 4.5 if invoking CC2695. This includes the rules of 4.5.2.1. You will need to use the UG-37 area replacement rules for nozzles with a ratio of greater than 1.5.
  12. pdiculous963

    UCS-68 (c) and Div. 2, temperature reduction for impact test exemption

    It does appear you are out of luck. Perhaps I did not get across my last point well. It was aimed at the actual failure mode rather than the Code rules. The impact test rules are there to ensure that a brittle fracture does not occur. To have a brittle fracture, you need cold enough...
  13. pdiculous963

    UCS-68 (c) and Div. 2, temperature reduction for impact test exemption

    Division 2 does not consider the PWHT to enhance the toughness, but rather to decrease the driving force to cause a fracture (weld residual stress). I completely agree with your second statement that the shell/welds cannot tell if they are PWHT or not. We have actually used similar wording in...
  14. pdiculous963

    UCS-68 (c) and Div. 2, temperature reduction for impact test exemption

    Division 2 has separate curves for PWHT and non-PWHT. See Figures 3.7 and 3.8 of VIII-2. It has nothing to do with if PWHT is required or not. If your vessel is PWHT, then you use the PWHT curves. If it is not, then use the non-PWHT curves. The intention of these curves were to explicitly...
  15. pdiculous963

    MDMT Flat head

    Either a stress reduction was used as permitted by UCS-66 or it could have been done wrong. Alternatively, if it was fabricated prior to the introduction of low temperature requirements (1987 Edition of the Code) carbon steels could go down to as low as -20°F prior to requiring impact testing...
  16. pdiculous963

    Stacked Repads?

    I've seen it done before. Its not an idea solution, but it isn't prohibited. The guy who performed the calculations was also an active member on the Code committee.
  17. pdiculous963

    Hi all Hope u all are well. Can a

    Yes, if you are not using a reinforcement pad, then te becomes zero and A5 and A42 are zero. However, Appendix 1-10 was removed from the 2017 Edition of the Code. If you are building to the 2017 version, I would suggest using the Div. 2 rules under Code Case 2695.
  18. pdiculous963

    NOZZLE ANALYSYS USING CAESAR II

    API 661 has a table for maximum forces and moments by nozzle size. To check in CAESAR, you need to select the "Nozzle Lmt Check" in the input box and put in the maximum forces and moments and select a comparison method. CAESAR will then check the applied loads compared to the maximum loads...
  19. pdiculous963

    subsection for stress imposed due to the static load of contents and wind load

    The formulas are strength of materials calculations. The column is essentially treated as a beam. Appendix L has been removed from the Code. I suggest reading PTB-4 for example problems. The examples are much more clear.
  20. pdiculous963

    Hex meshing of intersecting solid cylinders

    I'm guessing your part is a shell part based upon the mesh of the intersecting cylinders. If you want to use hexahedral elements (3D continuum elements), it needs to be be a solid part.

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