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  1. r77

    asme B31.3 Appendix P question (stress range)

    bigHinch, Of course, subscripts 1 & 2 refer to Operating case 1 and Operating case 2 I definitely agree with you, the definition of operating stress range is numerically the same than displacement stress range, apart from axial stress inclusion. A big difference seems to be, on the other hand...
  2. r77

    asme B31.3 Appendix P question (stress range)

    My doubts are not related to allowable stress(in this sense the appendix P is clear, Sa=1.25f(Sc+Sh)), but to the definition of <<operating stress range>> Se. The standard gives no formula, it just refers to the same formula used for the displacement stress range (319.4.4). Can operating stress...
  3. r77

    asme B31.3 Appendix P question (stress range)

    Hi all! There is something I can't grasp about stress range calculation according to the asme B31.3 appendix P. It says : <<The operating stress range is the range of STRESS between any two operating conditions..>>. This is a different definition than that given in 319.2.3 (b) : <<the...
  4. r77

    piping linear modal analysis and nonlinear support

    Ok, but can you assess a priori whether a dynamic analysis is important? can you decide to replace all sleepers with hold-downs just because your client asked for a seismic assessment? I think such a decision should be backed by calculations, so we are again back to the old question: there is a...
  5. r77

    piping linear modal analysis and nonlinear support

    Hi BigInch, As you say the best would be considering separately the two modes. But this becomes soon cumbersome if you have many such supports,as you should calculate all possible combinations. My idea is, to avoid a nonlinear transient analysis, to ignore the support at all. this would be...
  6. r77

    piping linear modal analysis and nonlinear support

    I quote BigHinch : <<there is a resulting net reaction that is in only one direction of the two possibilities, up or down>>, As far as static analysis is concerned I agree with you. As far as vibration and modal analysis are concerned there's something I don't understand: in vibrations analysis...
  7. r77

    piping linear modal analysis and nonlinear support

    Thank you 4Pipes for your explanation, I understand that if thare is no contact you can neglect the support; I'm less sure you can obtain correct results replacing a simple support with a full vertical restraint. What about ignoring the support in any case? best regards
  8. r77

    piping linear modal analysis and nonlinear support

    Hello forum, I'm approaching piping modal analysis and subsequent spectral recombination, and I need some help to undestand this point : modal analysis is a linear tool, so how can it be applied in the very ordinary situations where Y+ vertical supports are present (sleepers, saddles..etc)...

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