10 inch diameter pipe with 1E4 lb axial loading

SteveMeltonSteveMelton
looking at flange separation. prestress on rivets at .005 inch tension.











Comments

  • SergioSergio
    Nice work! What is the "stress_tt" variable?
  • disladisla
    Hello SteveMelton
    You comment on previous post that “I was able to apply bolt pre-tension by using offset nodes and the contact feature”
    Here it looks the same strategy.” prestress on rivets at .005 inch tension”
    ¿Do you mean you draw the bolt short and then impose a displacement to get the pre-tension.?
    Thanks
  • SteveMeltonSteveMelton
    Stress_tt = hoop stress. I am still trying to determine the formula for radial and tangential displacement.
  • VictorVictor
    Radial displacement is (x*u.x + y*u.y) / sqrt(x^2+y^2) which is the dot product of the normalized position vector and displacement.

    I think you can get tangential displacement with a cross product but not sure of the formula off the top of my head.

    Thanks for posting pictures of your work too. They're always very impressive.
  • SteveMeltonSteveMelton
    edited November 2018
    thx for the radial displacement.

    also, this 360 model makes it easy to add a moment to the flange. better than ANSYS.

    I like V10 beta. Faster graphics and right click position input for cut viewing. it's good.
  • SteveMeltonSteveMelton
    edited November 2018
    yes, draw the bolt short .005 and apply contact from the bolt face to the flange. CCX will prestress the bolt by that amount. in this case I also applied .3 friction factor to the bolt contact.
  • SteveMeltonSteveMelton
    new config. no load on the model, only prestress on the fasteners.




  • SteveMeltonSteveMelton
    edited November 2018
    final plot with moment on flange. hoop stress. flange face has no friction in this case.


  • disladisla
    " I am still trying to determine the formula for radial and tangential displacement"
    “I think you can get tangential displacement with a cross product but not sure of the formula off the top of my head”

    Nice challenge. :)
  • SergioSergio
    edited November 2018
    Is there any standard dimensions for preloading the bolt by displacement? I always preload up to 75-85% of material yield, mostly using the thermal procedure on a middle portion of the bolt flank. Normal torque procedure always remark that with n torque will lead to that stress on bolt.
  • SteveMeltonSteveMelton
    I think that could be useful. Correct, load the bolts close to yield. My favorite question, preload a single rigid flange bolt to 1000 lb and apply a 1000 lb load to the flange. What is the load on the bolt?
  • SergioSergio
    Bolt has no preload and the union start to gap?
  • SteveMeltonSteveMelton
    edited November 2018
    yes, what is the load on the bolt? 1000 lb
  • SergioSergio
    I don't understand your question, if you apply the load in the center of the flange, then will appear some flexion and moments on the bolts as is not in the same direction.
  • SteveMeltonSteveMelton
    some say, 1000 lb bolt preload + 1000 lb tension load = 2000 lb bolt load
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