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vessel in occean

vessel in occean

vessel in occean

I have a gas processing unit mounted on a giant ship. The vertical vessels (100' tall, 12' Dia) mounted on modular epxperiences waving angles with ocean waves. This vessel is filled with half liquid. Question:
1. How can supplier design this vessel per Div. 1?
2. Is this vessel to be considered in fatigue service due to cyclic stess caused by waving?

I received several bids among which shell thicknesses differ significantly.

Any contribution will be appreciated.


RE: vessel in occean

This really isn't a question specific to the computer program COMPRESS.  Suggest that you red-flag your post, and repost your question in the Boiler and Pressure Vessel Engineering forum.

RE: vessel in occean


I disagree with TGS4 because Compress is primarily a Div 1 design software AND since Div 2 can also be used in the "Design by Rule" mode the additional stress analysis required by Div 2 could compliment an essentially Div 1 design.

The majority of cases can still be investigated in Compress before considering fatigue.

Next, cyclic loading analysis can still be performed with a combination of hand calcs and Compress, and by following the instructions found in Div 2 but using Div 1 allowable stresses. There are also some FEA modules available that work with compress to perform Code calculations for fatigue.

Further, Compress has several tools that can represent additional load cases not directly included in the software. The result, if applied properly, will be slightly more conservative than a hand calculation would be but without spending 3 (additional) months of engineering on it due to repeatedly running all the various operating conditions usually included in PV calcs. (I could be exaggerating the time required to do this without Compress, but you get the picture)

Finally, you are trying to obtain some consistency in the bids during a time in the market where manufacturers are willing to roll the dice on their being able to deliver what you need in order to keep work in the shop.

Compress or not you know it will take a company with decent engineering to give you what you need.

If you are concerned that Compress has some error that is giving the bidders different answers then take some good advice from one of my professors "Always remember that a monkey with a tool is still just a monkey!"

good luck!

RE: vessel in occean


I strongly agree with you that a monkey with a tool is still just a monkey. I appreciate your valuable advise.
Can anyone pls share your experience of using COMPRESS to design fatigue vessel?

THX, PetroPV  

RE: vessel in occean

COMPRESS is not intended for fatigue analysis, it does not perform any analysis for this condition or cyclic service.

An exception is that the FEA-Nozzles feature (a special edition of the NozzlePRO software published by Paulin Research Group, included with COMPRESS for finite element analysis of nozzles) performs analysis for cyclic service and fatigue.

   "Although this forum is monitored by Codeware it is not intended as a venue for technical support and should not be used as the primary means of technical support."

  Tom Barsh
  Codeware Technical Support

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