Abstract

Offshore steel structures are widely used around the world, e.g., in Gulf of Mexico, the Middle East, and the North Sea. These structures are costly to build, and any damage to them could be catastrophic financially and environmentally. There are many factors that could possibly affect the health of these steel structures, particularly hydrodynamic forces. These forces cause the structure to vibrate and in the long run could lead to fatigue failure. Therefore, measures have to be taken in order to prevent these structures from failing. Magneto-rheological (MR) dampers are proven as a feasible alternative to reducing structural vibrations. An experimental setup is built in our laboratory to improve the dynamic modeling of steel jacketlike structures and study the effectiveness of MR dampers in decreasing the hydrodynamically induced vibrations. The structure is analyzed theoretically and experimentally, and the results are presented here.

1.
Zribi
,
M.
,
Almutairi
,
N.
,
Abdel-Rohman
,
M.
, and
Terro
,
M.
, 2004, “
Nonlinear and Robust Control Schemes for Offshore Steel Jacket Platforms
,”
Nonlinear Dyn.
0924-090X,
35
(
1
), pp.
61
80
.
2.
Terro
,
M.
, and
Abdel-Rohman
,
M.
, 2007, “
Wave Induced Forces in Offshore Structures Using Linear and Nonlinear Forms of Morison’s Equation
,”
J. Vib. Control
1077-5463,
13
(
2
), pp.
139
157
.
3.
Wilson
,
J. F.
, 2002,
Dynamics of Offshore Structures
,
Wiley
,
Chichester, UK
.
4.
Abdel-Rohman
,
M.
, 1996, “
Structure Control of a Steel Jacket Platform
,”
Struct. Eng. Mech.
1225-4568,
4
(
2
), pp.
125
138
.
5.
Horr
,
A. M.
, and
Safi
,
M.
, 2003, “
Full Dynamic Analysis of Offshore Platform Structures Using Exact Timoshenko Pipe Element
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
125
(
3
), pp.
168
175
.
6.
Doyle
,
J. F.
, 1989,
Wave Propagation in Structures
,
Springer-Verlag
,
Berlin
.
7.
Dyke
,
S. J.
,
Spencer
,
B. F.
, Jr.
,
Sain
,
M. K.
, and
Carlson
,
J. D.
, 1996, “
Modeling and Control of Magneto-Rheological Dampers for Seismic Response Reduction
,”
Smart Mater. Struct.
0964-1726,
5
, pp.
565
575
.
8.
Guan
,
X.
,
Li
,
J.
,
Wu
,
B.
, and
Ou
,
J.
, 2006, “
An Experimental Study of Magneto-Rheological Fluid Dampers for Vibration Control of One Off Shore Platform
,”
Proc. SPIE
0277-786X,
6169
, pp.
123
129
.
9.
Spencer
,
B. F.
, Jr.
,
Dyke
,
S. J.
,
Sain
,
M. K.
, and
Carlson
,
J. D.
, 1997, “
Phenomenological Model of a Magneto-Rheological Damper
,”
Journal of Engineering Mechanics, Trans. Of ASCE
,
3
, pp.
230
238
.
10.
Dyke
,
S. J.
,
Spencer
,
B. F.
, Jr.
,
Sain
,
M. K.
, and
Carlson
,
J. D.
, 1998, “
An Experimental Study of MR Dampers for Seismic Protection
,”
Smart Mater. Struct.
0964-1726,
7
, pp.
693
703
.
11.
Hitchcock
,
G. H.
,
Wang
,
X.
, and
Gordaninejad
,
F.
, 2007, “
A New Bypass Magneto-Rheological Fluid Dampers
,”
Trans. ASME, J. Vib. Acoust.
1048-9002,
129
, pp.
641
647
.
12.
Morison
,
J. R.
,
O’Brien
,
M. P.
,
Johnson
,
J. W.
, and
Shaaf
,
S. A.
, 1950, “
The Forces Exerted by Surface Waves on Piles
,”
Trans. AIME
0096-4778,
189
, pp.
149
154
.
13.
Borgman
,
L. E.
, 1967, “
Spectral Analysis of Ocean Wave Forces on Piling
,”
J. Wtrwy. and Harb. Div.
0569-8103,
93
(
WW2
), pp.
129
156
.
14.
Anagnostopoulos
,
S. A.
, 1982, “
Dynamic Response of Offshore Platforms to Extreme Waves Including Fluid-Structure Interaction
,”
Eng. Struct.
0141-0296,
4
, pp.
179
185
.
15.
Chang
,
M. T.
, and
Tung
,
C. C.
, 1990, “
An Approximate Method for Dynamic Analysis of Offshore Structures to Wave Action
,”
Eng. Struct.
0141-0296,
12
, pp.
120
123
.
16.
Najafian
,
G.
,
Tockell
,
R. G.
,
Burrows
,
R.
, and
Bishop
,
J. R.
, 2000, “
The UK Christchurch Bay Compliant Cylinder Project: Analysis and Interpretation of Morison Wave Force and Response Data
,”
Appl. Ocean. Res.
0141-1187,
22
, pp.
129
153
.
17.
Patil
,
K. C.
, and
Jangid
,
R. S.
, 2005, “
Passive Control of Offshore Jacket Platforms
,”
Ocean Eng.
0029-8018,
32
, pp.
1933
1949
.
18.
Penzien
,
J.
, 1976, “
Structural Dynamics of Fixed Offshore Structures
,”
Proceedings of the First International Conference on the Behavior of Offshore Structures
, Trondheim, Norway, Vol.
1
, pp.
581
592
.
19.
Guo
,
S.
,
Yang
,
S.
, and
Pan
,
C.
, 2006, “
Dynamic Modeling of Magneto-Rheological Damper Behaviors
,”
J. Intell. Mater. Syst. Struct.
1045-389X,
17
, pp.
3
14
.
20.
Liao
,
W. H.
, and
Lai
,
C. Y.
, 2002, “
Harmonic Analysis of a Magnetorheological Damper for Vibration Control
,”
Smart Mater. Struct.
0964-1726,
11
, pp.
288
296
.
21.
Spencer
,
B. F.
,
Dyke
,
S. J.
,
Sain
,
M. K.
, and
Carlson
,
J. D.
, 1996, “
Idealized Model of a Magneto-Rheological Damper
,”
ASCE Proceedings of the 12th Conference on Analysis and Computation
, Chicago, Illinois, pp.
461
470
.
22.
Doyle
,
J. F.
, and
Farris
,
T. N.
, 1990, “
A Spectrally Formulated Finite Element for Flexural Wave Propagation in Beams
,”
Int. J. Anal. Exp. Modal Anal.
1066-0763,
5
(
2
), pp.
99
107
.
23.
Gopalakrihnan
,
S.
,
Martin
,
M.
, and
Doyle
,
J. F.
, 1992, “
A Matrix Methodology for Spectral Analysis of Wave Propagation in Multiple Connected Timoshenko Beams
,”
J. Sound Vib.
0022-460X,
158
(
1
), pp.
11
24
.
24.
Horr
,
A. M.
, 1995, “
Energy Absorption in Structural Frames
,” Ph.D. thesis, University of Wollongong, Australia.
25.
Horr
,
A. M.
, and
Schmidt
,
L. C.
, 1996, “
Modelling of Nonlinear Damping Characteristics of a Viscoelastic Structural Damper
,”
Eng. Struct.
0141-0296,
18
(
2
), pp.
154
161
.
26.
Horr
,
A. M.
, and
Schmidt
,
L. C.
, 1997, “
Complex Fractional Spectral Method for Space Curved Struts: Theory and Application
,”
Int. J. Space Struct.
0956-0599,
12
(
2
), pp.
59
67
.
27.
Horr
,
A. M.
, and
Schmidt
,
L. C.
, 1996, “
Frequency Domain Dynamic Analysis of Large Space Structures With Added Elastometric Dampers
,”
Int. J. Space Struct.
0956-0599,
11
(
3
), pp.
279
289
.
28.
Horr
,
A. M.
, and
Schmidt
,
L. C.
, 1995, “
Closed-Form Solution for the Timoshenko Beam Theory Using a Computer-Based Mathematical Package
,”
Comput. Struct.
0045-7949,
55
(
3
), pp.
405
412
.
29.
Timoshenko
,
S. P.
, 1921, “
On the Correction for Shear of the Differential Equation for Transverse Vibrations of Prismatic Bars
,”
Philos. Mag.
1478-6435,
41
, pp.
744
746
.
30.
Horr
,
A. M.
, 1995, “
A Non-Linear Damping Model for Design of a Satellite Antenna
,”
First Conference on Space Technology and Developing Countries
, Tehran, Iran, Vol.
1
, pp.
233
239
.
31.
Horr
,
A. M.
, and
Schmidt
,
L. C.
, 1996, “
A Fractional-Spectral Method for Vibration of Damped Space Structures
,”
Eng. Struct.
0141-0296,
18
(
12
), pp.
947
956
.
32.
Peters
,
M.
, 2007, “
Fixed Platforms Remain Important Production Facilities After More Than 60 Years
,”
Offshore
0030-0608,
67
(
9
), Online first.
You do not currently have access to this content.