This is my first experience on an FPSO project. Based on the informations that I have gathered, it appears to me that the following load effects are to be considered ( besides: wind, blast, reaction force, nozzle displacements,slug etc)

1) Deformation of the hull . This will be due to static effects as well as wave effects.Both sagging and hogging effects have to be considered.

2) Acceleration due to heave, pich and roll ( this will be for both towing as well as static conditions). Of these three motions,pitch and roll should be rotational accelerations. However, I found that the typical way of giving acceleration input for pitch and roll is translational acceleration. Why? These accelerations will be SUS load cases.

3) Structural displacements due to the accelerations mentioned in (2).

4)Thermal effects.

Load cases will comprise of the following:

1) W+P+ SRSS of accelerations due to pitch, heave and roll.This will be checked against Sh.This is to be checked for both static as well as towing conditions.

2) Thermal displacement stress range + Displacement stress range due to hull deformation+ displacement stress range due to structural movements due to pitch,heave and roll. The method of summation will be ABS.This will be compared against the B31.3 stress range with stress range reduction factor =0.15.

3) Summation of thermal, weight and all displacement and acceleration loadings for equipment nozzle loading and pipe support loading.


Suggestions/guidelines/corrections from esteemed members of this forum will be highly appreciated.

Regards

Get in touch with the guys at KBR Leatherhead !

what is FPSO?
From your information, it should be a general analysis based on B31.3.

Stress river ... how wrong you are.

It's a floating production, storage and offloading vessel. Piping and equipment is subjected to large hull deformations (hogging, sagging), roll, heave etc, all the fatigue inducing motions of a top-heavy ship and wave slam in addition. Then there's the usual environmental and operating loads to consider.

Not quite a general analysis, and may require around 90 load cases for each Caesar input.

Dear MoverZ,

Thanks for the input.

Regards

Anindya,

At the Coade conference last October Bob Robleto of KBR Houston presented an excellent paper on exactly this subject. Maybe Bob, or Coade would let you have a copy.

Dear MoverZ,

Thanks a lot for this information.If I can get this on coade website, it is best. else i will ask Richard or Dave for help.

Regards

Anindya,

I could find some Load case combinations in App.G of DNV-RP-D101 to consider for the accelerations for Pitch, Heave and Roll.
I hope this would be of some help to you.

Regards,

Dear SKK,

Thanks for the input.

Regards

Anindya

Dear Anindya / Mover Z
Could you please share this paper to me.
"At the Coade conference last October Bob Robleto of KBR Houston presented an excellent paper on exactly this subject. Maybe Bob, or Coade would let you have a copy."

Thanks.

Prapeepd,

You need to contact Intergraph / Coade to get Bob Robleto's paper.

May I request to Intergraph to share Bob Robleto's paper if they have.

Does anyone help me out on my below problem ?

I am doing fatigue anlysis using CAESAR-II for an Offshore piping laying on the bridge between two platforms . I have 15 sets of wave height (varing from 1m wave height to 15m wave height) data vs it's number of occurance cycles. Each wave is to be analysed for 8 different displacement values at a single node. Now due to C-II's limitation of maximum displacement entries at a node is 9. Hence I need to create 15 separate C-II files for each wave height and then calculating cumulative fatigue damage in excel file.
Does any one help / can share their experience / methodology how they combine such 15 sets of wave height into a single and works with only single C-II file. Or anything to be done in CAESAR-II.

Hope my point is clear to reader.
Thanks!

I think you have no option ... it's time to fire up Excel / Access.