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Limiting values for Von Mises

  1. Nov 19, 2012 #1
    Hi there was wondering if anybody could help me.

    1). How to find the limiting values of Von Mises stress induced in concentric reducers?
    2). At what pressure concentric reducer will fail?
    3). Calculation for thickness (minimum required for fittings) for ASME 1500 class rating.

    Material properties:

    Yeild = 450Mpa
    Min. Tensile Strength = 535Mpa

    Burst pressure value: 76.8Mpa

    These questions have been forwarded to me after I had designed the reducer and created and FEA Results report. So asking for help with the above 3 questions.

  2. jcsd
  3. Nov 19, 2012 #2
    Since you already have the FEA results, can't you just compare the von Mises stresses in the simulation to fy/sqrt(3)? Do you know where to look? Where do reducers usually fail when they fail? If it is a fracture problem, then you have to be careful in meshing your part, and you might want to consult a specialist in that sort of damage.
  4. Nov 19, 2012 #3
    I don't understand. Aren't these the questions you answer in your report. I do in mine. You have the material limits and the resultant stresses from the FEA. These are all you need really to answer those or are we missing something?
    Last edited: Nov 19, 2012
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