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Question, We don't understand the way the expansion stress is checked according to the last revision of ASME B31.4, because we don't understand the resulting allowable stress: based on paragraph 403.3.2 of ASME B31.4 it should be as below, but it doesn't appear to be applied in AutoPIPE. Further, in AutoPIPE online manual (toolbar) the expansion stress is still the same of very old releases (it is referred to a paragraph not more available in ASME B31.,4). it will be very appreciated if You give us an explanation on how AutoPIPE calculates the allowable expansion stress for ASME B31.4 Ed. 2012.
Answer: For B31.4 (2009 and higher) AutoPIPE does calculate the unrestrained expansion allowable as per clause 403.3.2 explained below for AutoPIPE:
SA=f[1.25(Sc+Sh)- SL]
Where:
SA = Allowable expansion stressf = Fatigue factor (defined as "Range reduction factor" on Result Model Options dialog)Sc = 2/3 * Sy (Sy is the minimum yield defined on Pipe Properties dialog)Sh = 2/3 * Syt (Syt is the yield value at each temperature case, updated on pressure and temperature dialog)SL = Sustained stress for unrestrained lines
Question: For ASME B31.4, why are the fields "Use nominal thickness" and "Use nom. Thk. for Hoop" unchecked in AutoPIPE V8i 09.06.00.15?
Answer: This is correct and our implementation is inconsistent with our online help as well. A new enhancement (TFS-75309) has been logged to update the online help.
Question: Using AutoPIPE V8i 09.06.00.15, with ASME B31.4, on the input grid Piping Restraint tab shows, stress equation column:
On Tools> Model Options> Results> :
Answer:
The Xtra Data option Piping Restrain is only used to control which combinations are displayed on the output report, result grid and interactive scan. AutoPIPE classifies certain equations as Restrained, and others and unrestrained and performs the calculations accordingly.
When the Result Model Option "Use rest. long. code eq." option is checked, AutoPIPE then uses the exact code equation to calculate the Longitudinal stress regardless of the support configuration and actual forces.
Question: What is the procedure to apply if we want to consider the Von Mises (maximum distortion energy theory) combination?
To be able to see all the combinations, use the XTRA DATA option "Show Both" to enable AutoPIPE to show all types of equations. Also, using Equivalent will allow user to see the equations as were available in earlier editions like B31.4 (2006). Hope this helps. Please thank the user from our side for taking the time out to point these issues out to us, we appreciate that.
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