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  1. JohnLL

    Beam Element

    Guys it might seem easy question, but as a non-expert in FEA, your answers is quite helpful here! Assume we model a structure (let's say a frame) using beam elements. The cross section is I-beam and we define it by geometry. Now after solving the job, we have bending moments, axial forces, etc...
  2. JohnLL

    Installation of Flexible Riser

    GRoStruc, Based on what you said, Now I am getting worried about another issue. During operation, Our flexible risers (there are two of them connected to sea surface turret) are supposed to be clamped to each other by buoyancy modules. So, there should be connections between buoys used for Lazy...
  3. JohnLL

    Installation of Flexible Riser

    GRoStruc, That was quite a helpful reply. I checked also the references you made. Do you also have any comment on installing the buoyancy tanks? Considering a Lazy wave riser which the flexible riser first is laid on seabed and later will be retrieved for connection to sea surface facility...
  4. JohnLL

    Again About Washers in subsea application

    There was a thread in this forum about "using washers in subsea bolted connections" (thread311-296001). It was suggested there that no washers are usually used in subsea applications. But why? As washers are required to provide larger pressure area, avoid component (let's assume flanges) damage...
  5. JohnLL

    Installation of Flexible Riser

    Guys! Anybody who is kind enough to briefly explain to me (or recommend a good reference) about: 1-the procedure of installing flexible risers on the seabed and attaching them to let's say a subsea manifold/PLEM. (I know it should be very similar to pipeline initiation, laying and lay-down but...
  6. JohnLL

    Offpipe software

    I guess there is no such software. However, it is possible to prepare input files as .txt files using a word processor (Notepad as simplest one). It will be more convenient if you use OFFPIPE interface in first place. Modify the input file text for detailed analysis or future use is then easy.
  7. JohnLL

    3LHDPE or 3LPP?

    Steve thanks for reply. to my best knowledge, in external pipeline coating application, what mainly differentiates between PE and PP is working temperature. Since my case has to operate at 90 deg. Celsius, PE addressed in DNV-RP-F106 can not be used, but PP can. Now we have HDPE tolerates...
  8. JohnLL

    3LHDPE or 3LPP?

    I have a offshore pipeline which typically has to be coated with 3LPP, due to operating temperature and subsea application. Pipe will be also coated by concrete coating. Now there is an offer to use 3LHDPE. Question is: - Is there any drawback for 3LHDPE compared to 3LPP? - 3LHDPE is not...
  9. JohnLL

    Ball Valves: Carbon Steel Trim

    Dear SNORGY thanks for your complete reply. My understanding from your response is that although in THEORY it is possible to use CS, PRACTICALLY no body take the risk. It agrees with my experience, while I have not seen any valve with just CS ball/seat without overlay. But it remains under...
  10. JohnLL

    Ball Valves: Carbon Steel Trim

    I was wondering if it is possible to use carbon steel ball and seats -without overlaying- in a ball valve with: -oil service with no H2S no CO2 -low corrosion in pipeline, but as per DNV assumed 3mm (min. value) The standards (ISO, API) have general expression about suitability of material...
  11. JohnLL

    Contingency on Sacrificial Anode

    Hope this forum will be the right place to ask it! I need a figure how much contingency should be considered when issuing the requisition for sacrificial anodes for offshore pipeline? does a 10% contingency would cover all spares and contingencies due to any damage or loss? what is the typical...
  12. JohnLL

    Contingency on Sacrificial Anode

    I need a figure how much contingency should be considered when issuing the requisition for sacrificial anodes for offshore pipeline? does a 10% contingency would cover all spares and contingencies due to any damage or loss? what is the typical value for that in the industry? thanks
  13. JohnLL

    Again About DBB, DIB and DPE

    I have read almost all of the topics in Eng-tips about ball valves and Double block and bleed (DBB), Double Isolation and Bleed (DIB), etc. I also read the API 6D definitions and tests (DIB-1 and DIB-2). BUT STILL STUCK THERE! I would appreciate if somebody can answer my question, put in simple...
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