Dear SACS expert,
Need your help,
How to describe S-N curve above water level (for example at jacket walkway level).
Any specific option at SACS fatigue input?
S-N curve in SACS fatigue can be chosen from code library or defined by user self in stress-cycles curve format in FTOPT command line.
Hi Kevin,
Just to confirm, which S-N curve between 'air' and 'sea water' used by SACs for element located in 'Splash Zone' ?
Regards,
Kasiphon
Hi Kasiphon,
Are you asking which option of S-N curve source in SACS has a separate curve for element located in splash zone?
I mean when some member located in splash zone, SACs will consider as they locate in air or in water.
i.e. Assume water line is EL+0m and splash zone = EL-5 to EL+5.
If we have member \ joint located in this range. SACs will use SN in air or in water to calculate fatigue.
Or SACS do not care about splash zone and use water line instead i.e. below EL+0m will be used SN in water and above EL+0 will be used SN in air.
Btw, SACS also require user to define splash zone in ftginp. What is the purpose for splash zone elevation in ftginp ?
Except you define S-N curve manually, SACS strictly abide for the code your selected. For example
Just to confirm,
Fex, I select SN curve from SACS library i.e. NT (NORSOK T curve).
In FTOPT2 Col. 37-50, we can also define Splash zone which I understand this zone will be actively used for AXX SN curve only (API thickness dependent curve), please confirm.
However, refer to DNV-RP-C203, it is recommend to use 'SN in Seawater' for joint located in Splash zone.
Then, if splash zone is -5 to +5, the joint located at EL+2 is already above water line (Assume water line is EL+0). SACS will pick SN in Air to check this joint fatigue. As SACS use water line to classify the SN curve, please confirm.
If I would like to use SN in Seawater for joints locate from EL+5 to mudline , How can I do in SACS ?
Kevin,
Another question,
As you said, SACS use water line to classify type of SN curve,
However, they are no water depth and mudline in ftginp ! How SACS know the elevation of Water line ???
Fex, you can call only *.CSFs to calculate fatigue. Is water depth and mudline infomation also store in CSF file?
Btw, they are col. 54-67 which allow to input mudline and water depth.
However, SACS manual said that it is for HSE, API, WJ and ISO....Then, what is about NORSOK and other curve that are not mentioned in the manual ? How SACs know the elevation of waterline for the rest of the curve?
Thank for your response. It is broaden my knowledge a lot !