Product(s):	SACS
Version(s):	23.00
Area:	SACS Fatigue

Question

For in-line connections or segmented tubular section changes, the default SCF method is designated in columns 51-53 on the FTOPT2 line. DNV, DN2 and DN3 are three out of twelve options available for in-line SCF. Can you provide the equations of these three DNV methods?

Solution

1) ‘DNV’ - SCFs suggested by Det Norske Veritas.

It is a reformulation of the Maddox formula except it raises the thickness to the power of 2.5 instead of 1.5. The earliest documentation of DNV RP C203 is from 2001 which uses a slight modification of the Maddox formula (including eccentricity). In any case, this option should not be used except for historical purposes.

2) ‘DN2’ – SCFs suggested by DNV RP-C203 (2005)

It is conservative to use the formula for plate eccentricities for calculation of SCF at tubular butt welds. The effects of the diameter in relation to thickness may be included by use of the following formula, provided that T/t ≤ 2

3) ‘DN3’ – SCFs suggested by DNV RP-C203 (2008).

It is conservative to use the formula for plate eccentricities for calculation of SCF at tubular butt welds. The effects of the diameter in relation to thickness may be included by use of the following formula, provided that T/t ≤ 2

See Also

SACS Fatigue Manual, Section 3.2 for other default SCF Method