Finite element analysis is being used by designers for fatigue assessment of structures. It is therefore important that a proper link between calculated hot spot stress and fatigue capacity is established. The fatigue capacity is expressed as a hot spot stress S-N curve. This paper presents a derivation of a hot spot stress S-N curve to be used when the hot spot stress is derived from finite element analysis of plated structures. The hot spot S-N curve is linked to the methodology used for finite element analysis of plated structures that is being included in design recommendations for fatigue assessment of welded structures.

1.
Fricke
,
W.
, and
Petershagen
,
H.
, 1992, “
Detail Design of Welded Ship Structures Based on Hot Spot Stresses
,” PRADS, Newcastle.
2.
Lotsberg
,
I.
,
Cramer
,
E.
,
Holtsmark
,
G.
,
Løseth
,
R.
,
Olaisen
,
K.
, and
Valsgård
,
S.
, 1997, “
Fatigue Assessment of Floating Production Vessels
,”
Proceedings of the 8th International BOSS Conference
, July 7–11, Delft, The Netherlands,
J. H.
Vugts
, ed.,
Elsevier
, Vol.
3
, pp.
93
107
.
3.
Lotsberg
,
I.
, 2000, “
Background and Status of the FPSO Fatigue Capacity JIP
,”
OTC-2000 Offshore Technology Conference
, May 1–4, Houston, TX.
4.
Lotsberg
,
I.
, 2001, “
Overview of the FPSO Fatigue Capacity JIP
,”
20th International Conference on Offshore Mechanics and Arctic Engineering
, June 3–8, Rio de Janeiro, Brazil.
5.
DNV-RP-C203
, 2005, “
Fatigue Strength Analysis of Offshore Steel Structures
,” DNV, Oslo.
6.
DNV CN 30.7
, 2005, “
Fatigue Strength Assessment of Ship Structures
,” DNV, Oslo.
7.
Maddox
,
S.
, 2001, “
Recommended Design S-N Curves for Fatigue Assessment of FPSOs
,”
Proceedings of the 11th International Offshore and Polar Engineering Conference
, June 17–22, Stavanger, Norway.
8.
Kang
,
S. W.
, and
Kim
,
W. S.
, 2003, “
A Proposed S-N Curve for Welded Ship Structure
,”
Weld. J. (Miami, FL, U.S.)
0043-2296
82
(
7
), pp.
161
168
.
9.
Fricke
,
W.
, 2001, “
Recommended Hot Spot Analysis Procedure for Structural Details of FPSO’s and Ships Based on Round-Robin FE Analyses
,”
Proceeding 11th ISOPE, Stavanger; also International Journal of Offshore and Polar Engineering
,
12
(
1
), pp.
40
47
.
10.
Lotsberg
,
I.
, 2004a, “
Recommended Methodology for Analysis of Structural Stress for Fatigue Assessment of Plated Structures
,”
Proceedings of the OMAE Specialty Symposium on Integrity of Floating Production, Storage and Offloading (FPSO) Systems
, August 30–September 2, Houston, TX.
11.
Lotsberg
,
I.
, 2006, “
Fatigue Design of Plated Structures using Finite Element Analysis
,”
J. Ships Offshore Struct.
,
1
(
1
), pp.
45
54
.
12.
IIW
, 1996, “
Fatigue Design of Welded Joints and Components. Recommendations of IIW Joint Working Group XIII-1539-96/XV-845-96
,” edited by A. Hobbacher Abington Publishing, The International Institute of Welding.
13.
Bergan
,
P. G.
,
Lotsberg
,
I.
,
Fricke
,
W.
,
Francois
,
M.
, and
Pisarski
,
H.
, 2002, “
Overview of Phase II of the FPSO Fatigue Capacity JIP
,”
21st International Conference on Offshore Mechanics and Arctic Engineering
, June 23–28, Oslo, Norway.
14.
Bergan
,
P. G.
, and
Lotsberg
,
I.
, 2006, “
Fatigue Capacity of FPSO Structures
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
128
, pp.
156
161
.
15.
Kim
,
W. S.
, and
Lotsberg
,
I.
, 2004, “
Fatigue Test Data for Ship/FPSO Specific Details
,”
Proceedings of the OMAE Specialty Symposium on Integrity of Floating Production, Storage and Offloading (FPSO) Systems
, August 30–September 2, Houston, TX;
Kim
,
W. S.
, and
Lotsberg
,
I.
, 2005
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
127
(
4
), pp.
359
365
.
16.
Fricke
,
W.
,
Doerk
,
O.
, and
Gruenitz
,
L.
, 2004, “
Fatigue Strength Investigation and Assessment of Fillet-Welds Around Toes of Stiffeners and Brackets
,”
Proceedings of the OMAE Specialty Symposium on Integrity of Floating Production, Storage and Offloading (FPSO) Systems
, August 30–September 2, Houston, TX.
17.
Choo
,
Y. S.
, and
Zahidul Hasan
,
M.
, 2004, “
Hot Spot Stress Evaluation for Selected Connection Details
,”
Proceedings of the OMAE Specialty Symposium on Integrity of Floating Production, Storage and Offloading (FPSO) Systems
, August 30–September 2, Houston, TX.
18.
Kang
,
S. W.
,
Kim
,
W. S.
, and
Paik
,
Y. M.
, 2002, “
Fatigue Strength of Fillet Welded Steel Structure Under Out-of-Plane Bending Load
,”
Int. J. Korean Welding Soc.
,
6
, pp.
33
39
.
19.
Berge
,
S.
, 1984, “
Effect of Plate Thickness in Fatigue Design of Welded Structures
,” OTC Paper No 4829, Houston.
20.
Zettlemoyer
,
N.
, and
Fischer
,
J. W.
, 1978, “
Stress Gradient Correction Factor for Stress Intensity at Welded Gusset Plates
,”
Welding Research Supplement
, February, pp.
57
62
.
21.
Eurocode 3
, 2003, “
Design of Steel Structures. Part 1-1: General Rules and Rules for Buildings
,” prEN 19993-1-1:2003.
22.
Lotsberg
,
I.
, and
Landet
,
E.
, 2005, “
Fatigue Capacity of Side Longitudinals in Floating Structures
,”
Mar. Struct.
0951-8339,
18
, pp.
25
42
.
23.
Lotsberg
,
I.
, 2004b, “
Fatigue Design of Welded Pipe Penetrations in Plated Structures
,”
Mar. Struct.
0951-8339,
17/1
, pp.
29
51
.
24.
BS 7910, 1999, “
Guide on Methods for Assessing the Acceptability of Flaws in Fusion Welded Structures
,” British Standard.
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