Dear All
I am doing a subsea riser analysis based on DNV . in which i have to key input all the material properties but i am stuck with the values of SY1,SY2,SY3...etc and UTS1,UTS2..etc. when i have tried to get explanation from help regarding these values i got the reply which i am given below:

(1)for SY values: SH Typically the hot allowable stress for the specific material taken directly from the governing piping code(but nothing mentioned about DNV code)
(2)For UTS values: Fn Stress range reduction factor for most piping codes,for DNV - This is the material ultimate tensile strength at temperature. is this is the De-rated values of tensile strength? please explain to me.

I am confusing with this explanations because the notations are different in CAESARII window and Help screen.
If any one can clarify these please do it.

Thanking you.

1) The help text is generic unless otherwise stated. In the case of these fields, the DNV code does not provide material property information.

2) I believe the de-rating factors were introduced in the 2000 Edition. CAESAR II implements DNV 1996 (Allowable Stress Design), which requires usage factors. These are entered in the Ns, Nu, Sy, and N fields at the bottom.

I suggest you re-read the DNV code.

Some materials e.g. API, do have maximum yield and maximum tensile values in the DNV code table 13-4. The the derating factors can be found on a graph in figure 2. Or you get the values from the pipeline vendor.

Then there are the other factors as mentioned above in Richard's reply.

The same values should have been used to calulate the wall thickness.

You will also need to consider what load cases you need to run to meet DNV code.