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  1. DarcyDude

    Writing Limit Margins when Plastic Deformation Occurs

    Hello All, Thanks again for the replies/discussions! I think maybe the thread of discussion deviated a bit from my intent. I agree that these localized stresses are either a) fictitious, b) not of concern, or c) a combination of both. However, being more industrial focused in my career, I am a...
  2. DarcyDude

    Writing Limit Margins when Plastic Deformation Occurs

    Hello all, Thanks for the replies! SW, thank you for your guidance. I was intending to extract loads to margin the fastener and associated checks, but was maybe overthinking how far from the rigid should be ignored on the base part. I have heard to exclude the first 2X rows of elements...
  3. DarcyDude

    Writing Limit Margins when Plastic Deformation Occurs

    SW, Correct, I am modeling with rigids at fastener hole and agree the rigid will introduce artificially high stresses. Honestly, I am always a bit fuzzy when to draw the line as to when nodes are far enough away from the rigid that results are no longer fictitious. I provided an image below...
  4. DarcyDude

    Writing Limit Margins when Plastic Deformation Occurs

    Hello all, Not exactly aircraft engineering, but I believe this group would have the best understanding of these topics. I work for a small company that typically designs fixed GSE. However, we are working a skid mounted project which we must verify against transport loads per MIL-STD-1791...
  5. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    So reading through the recommended documents PVP2013-97814 and WRC 538 both provide good insight into design and limitations of flanged joints, and talk through all elements (flange, bolting, gasket, etc.). Short reads and very helpful. Interestingly both were written by the same fellow. Both...
  6. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    Sorry it appears XL83NL may have already provided some guidance here: https://www.eng-tips.com/viewthread.cfm?qid=350904 I will try to get my hands on PVP2013-97814
  7. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    to clarify "If the ASME **Appendix 2** method is only suitable for flange design from a strength perspective..."
  8. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    Hello BJI, Thank you for the detailed response. I have not had a change to get into find detail, but after an initial skim through WRC 538 seems like the best resource I have yet come across for answering these questions. If the ASME method is only suitable for flange design from a strength...
  9. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    LI, You are definitely correct, I was not thinking about the scenario properly. Last night I started looking through ASME BPVCE SECTION VIII DIV 1 APPENDIX 2 (RULES FOR BOLTED FLANGE CONNECTIONS WITH RING TYPE GASKETS), which seems to handle the behavior you mention with factor m and y where y...
  10. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    LittleInch, I think that helped shed light on the situation. I haven't gotten a chance to dig deeply into PCC-1 yet but it appears, as the paragraph you cited from 16.5 alludes, that depending how you navigate PCC-1 you could end up with different joint preloads. And thus different flanged...
  11. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    Thanks XL83NL for the PCC doc reference! So it does look like some joint analysis is generally required. Re reading my question, my first item was maybe a bit unclear. I understand that the ASME design may not specifically dictate a FOS to joint separation, but if we were to theoretically...
  12. DarcyDude

    ASME B16.6 Joint Separation Factors of Safety and Preload Joint Analysis

    Hello all, New to posting so apologies if I mis-step. I found a few posts on this topic but none reached a satisfying conclusion before being closed (satisfying to me anyway!) My question is theoretical and is sort of two fold: 1) Does anyone know any resources citing the factor of safety to...
  13. DarcyDude

    Pressure drop in compressible flow

    Hello all, For what its worth this is a pretty common item in aerospace. In my experience the preferred procedure is to model as "Fanno Flow", i.e. the equations goutam_freelance provided. This needs to be solved iteratively, and if setting up code to perform this procedure it is ideal to...

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