Abstract

In this work, economical design implementation of a circular steel monopod-offshore-tower, which is subjected to the extreme wave loading, is presented. The mass of the tower is considered as the objective function. The thickness and radius of the cross section of the tower are adopted as design variables of the optimization. Moreover, stress or buckling is specified as probabilistic constraints. The numerical strategy employed for performing the optimization uses the International Mathematics and Statistics Library (IMSL) routine that is based on the sequential quadratic programming. The first-order reliability method (FORM) is used for the reliability calculation from a specified limit state function based on the stress or buckling. A demonstration of an example monopod tower is presented.

1.
Enevoldsen
,
I.
, and
Sorensen
,
J. D.
, 1994, “
Reliability Based Optimization in Structural Engineering
,”
Struct. Safety
0167-4730,
15
, pp.
169
196
.
2.
Rackwitz
,
R.
, 2001, “
Reliability Analysis, A Review and Some Perspective
,”
Struct. Safety
0167-4730,
23
, pp.
365
395
.
3.
Wang
,
J.
, and
Ghosn
,
M.
, 2005, “
Linkage-Shredding Genetic Algorithm for Reliability Assessment of Structural System
,”
Struct. Safety
0167-4730,
27
, pp.
49
72
.
4.
Cheng
,
J.
, 2007, “
Hybrid Genetic Algorithm for Structural Reliability Analysis
,”
Comput. Struct.
0045-7949,
85
, pp.
1524
1533
.
5.
Madsen
,
H. O.
,
Krenk
,
S.
, and
Lind
,
N. C.
, 1986,
Methods of Structural Safety
,
Prentice-Hall
,
Englewood Cliffs, NJ
.
6.
Melchers
,
R. E.
, 2001,
Structural Reliability Analysis and Prediction
,
Wiley
,
Chichester, England
.
7.
Ramu
,
P.
,
Qu
,
X.
,
Youn
,
B. D.
,
Haftka
,
R. T.
, and
Choi
,
K. K.
, 2004, “
Safety Factor and Inverse Reliability Measure
,”
Proceedings of the 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
, Palm Springs, CA.
8.
Lee
,
J. O.
,
Yang
,
Y. S.
, and
Ruy
,
W. S.
, 2002, “
A Comparative Study on Reliability Index and Target-Performance Based Probabilistic Structural Design Optimization
,”
Comput. Struct.
0045-7949,
80
, pp.
257
269
.
9.
Eboli
,
C. R.
, and
Vaz
,
L. E.
, 2005, “
Optimization of Plane Trusses With Constraints in the Reliability Index Beta
,”
Proceedings of the Sixth World Congresses of Structural and Multidisciplinary Optimization
, Rio de Janeiro, Brazil.
10.
Jendo
,
S.
, and
Kolanek
,
K.
, 2002, “
Reliability Based Optimization of Spatial Shell Truss Under Multi-Loading Condition
,”
Proceedings of the Workshop on Reliability Based Design and Optimization, RBO 2002
, Warsaw, Poland.
11.
Karadeniz
,
H.
,
Togan
,
V.
, and
Vrouwenvelder
,
T.
, 2008, “
Reliability Based Optimization of Steel Monopod Offshore Towers
,”
Proceedings of the ASME 27th International Conference on Offshore Mechanics and Arctic Engineering, OMAE-2008
, Estoril, Portugal.
12.
Det Norske Veritas (DNV)
, 1992,
Buckling Strength Analysis, Classification Notes
,
DNV
,
Hovik, Norway
.
13.
Uys
,
P. E.
,
Farkas
,
J.
,
Jarmai
,
K.
, and
van Tonder
,
F.
, 2007, “
Optimization of a Steel Tower for a Wind Turbine Structure
,”
Eng. Struct.
0141-0296,
29
, pp.
1337
1342
.
14.
Karadeniz
,
H.
, 2005, “
Reliability Calculation of RC Offshore Structures Under Extreme Wave Loading
,”
Proceedings of the 15th International Offshore and Polar Engineering Conference, ISOPE-2005
, Seoul, Korea.
15.
Lancaster
,
E. R.
,
Calladine
,
C. R.
, and
Palmer
,
S. C.
, 2000, “
Paradoxical Buckling Behavior of a Thin Cylindrical Shell Under Axial Compression
,”
Int. J. Mech. Sci.
0020-7403,
42
, pp.
843
865
.
16.
StuPOC V
, 1979,
Probabilistic Reliability Analysis for Offshore Structures, Final Report
,
Netherlands Industrial Council for Oceanology
,
The Netherlands
.
You do not currently have access to this content.