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# Wall Thickness Design

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 Chembloke99 (Chemical) 14 Jun 09 23:39
 I am doing wall thickness calculation for subsea pipeline based on DNV-F-101 spreadsheet. In the spreadsheet, I am stuck as I don't know the values that I should fill for the following parameters:M F =Static moment due to curvature in the pipeS F =Static effective axial forceM E =Environmental moment from vessel motions and hydro dynamic forcesS E = Environmental effective axial from vessel motions and hydro dynamic forcesεF & εE  = functional and environmental strain respectively.I have seen a reference document for 6" and P= 861 PSI pipeline, in that spread-sheet following values have been filled:M F =empty S F =empty M E =54.32 (based on experiment it is 0.85 SMYS)S E = 170(based on experiment it is 0.10 SMYS)εF & εE  = 0 & 0.15Can anyone explain it to me how can I find out these values for 8" pipeline and design Pressure = 1600 PSI and temp = 77 deg C.? Any help would be greatly appreciated.Thanks.
 subsealinepipe (Mechanical) 1 Oct 09 6:43
 For wall thickness calculation as per DNV-OS-F101, the follwoings shall be checked:1) Pressure containment (buresting)2) Local buckling - external over pressure only (system collapse)3) Propagation bucklingIn general local buckling - combined loading criteria should be checked in other assessments (i.e. free spans, upheaval/lateral buckling, installation)What you have pointed out are functional and environmental loads required only for local buckling-combined loading criteria, and their value shall be calculated via either a FEM or manually. Sincerely,Amir Naghashan
 DSB123 (Mechanical) 1 Oct 09 7:34
 Chembloke99,             Not trying to be negative but if you are trying to use a "spreadsheet" or any other form of calculation/software then you should have a grasp of the Codal requirements and the software/spreadsheet before tackling. Just filling in numbers is not the corrct approach. I suggest you refer to someone with more competency in the type of calculation you are attempting to undertake.
 Chembloke99 (Chemical) 3 Oct 09 2:50

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