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Recent content by jrjones

  1. jrjones

    Axisymmetric Equivalent Bolts for pipe flange connections

    Folks, I'm trying to find a source that would describe how to axisymmetrically model a flanged joint. Specifically, I have always made an equivalent plane strain "bolt" by matching both the cross sectional areas and the moments of inertia for a single stud (bolt) and the equivalent axisymmetric...
  2. jrjones

    Creating a Tapered Thread (Solid 3d model)

    Okay, a while back I asked about how to create a thread (or spring) helical pattern in CAE. Duh, of course the answer was to specify a pitch when rotating a sketch to create a solid. Now to the next level, I want to create a small section of tapered thread. This means that I have to model a...
  3. jrjones

    API653 - Low Nozzle Problems.

    I agree with khardy about the "proper evaluation". I have run into this exact senario a few times for a few clients. Rather than looking for loop holes, etc, I have just built quick FEA models of the nozzles to show that even during hydro conditions the nozzle stresses are acceptable. You...
  4. jrjones

    pneumatic testing of fuel oil tank?

    For standards used to perform air tests on vessels that consider stored energy, etc., there is a decent document developed by NASA. I will try to find the document and attach it in a follow up post. It was used to show management at the refinery that used to work at that air testing (~250 psig)...
  5. jrjones

    Fatigue Analysis in Cyclic Service

    You can use the new Section VIII Div. 2 to perform a more detailed fatigue assessment of a Div. 1 vessel. The new S8D2 (along with the new API 579-1/ASME FFS-1) cover off the fatigue design better especially for welds where the structural stress method is used. As for the controling...
  6. jrjones

    Modeling a coil spring in Abaqus

    Duh...pitch...thanks, forgot about the pitch specification. Thanks
  7. jrjones

    ASME Section 8 Div 2 (2007), Plastic Strain Limits

    Just wondering if anyone out there knows where the equation for the triaxial strain limit in the new S8D2 5.3.3 comes from? It is also in the new API 579. Specifically I am looking for a derivation of the equation so as to determine how the m_2 and alpha_sl coefficients come from. el=elu x...
  8. jrjones

    Modeling a coil spring in Abaqus

    I am trying to figure out a way to model a coil (helical) in CAE. Any ideas how to do this easily?
  9. jrjones

    API Steel Dome Roof Tanks

    I have found "Above Ground Storage Tanks" by Philip E. Myers to be a decent resource for tank design in general with some good info on roof design. Check it out on Amazon.
  10. jrjones

    Film Coefficients for Internal Pipe Flow

    I am trying to find a range of values for film coefficients on the internal of an 8" pipe. Problem is, I don't (as yet) have much info on the fluid other than it is mixed hydrocarbons, ~950°F, with a flow rate in the range of 147000 lbs/hr. I just don't have a good feel for what the range of...
  11. jrjones

    Nozzle loads, primary or secondary.

    Thanks for the discussion. I did have an issue with calling the nozzles stresses secondary. My issue is that I question myself because when I read the 2007 section 8 div 2, bending in the nozzle wall is to be treated as secondary. This is in the table for a description that says for all...
  12. jrjones

    Nozzle loads, primary or secondary.

    I found the WRC bulletin and will read up...I don't have access to the older S8D2...TGS4, do you know where I could find the "criteria" document you referred to..? Thanks for the help. Ryan
  13. jrjones

    Bottom seam layout in flat bottom tank

    JStephen, I don't have my 650 handy right now...but I thought there was a figure that showed weld spacing both in the floor and shell. I thought that on that figure it gave guidelines on the angle between the shell and the lap weld seams. I will check my book on monday.. Ryan
  14. jrjones

    Nozzle loads, primary or secondary.

    Okay, before I get in trouble, I know that there are a couple of threads out there on this topic...but as yet I am not satisfied. I am trying to analyze a nozzle (specifically the nozzle wall) using the 2007 ASME section 8 div 2 (S8D2) analysis. First of all, my nozzle configuration is made up...
  15. jrjones

    Re-testing frozen process pipe systems

    If you froze a pipe you may way to do some diameter checks to make sure the pipe hasn't dilated significantly. Especially look near any restraints (supports, vents, drains, tees, etc). Even if you find some dilation, you could probably apply the general 1% rule for out of roundness from most...

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