In this first part of a two-part study, the general nonlinear system identification methodology developed earlier by the authors for a single-degree-of-freedom (SDOF) system using the reverse-multi-input/single-output (R-MI/SO) technique is extended to a multi-degree-of-freedom (MDOF), sub-merged, moored structure with surge and heave motions. The physical nonlinear MDOF system model and the formulation of the R-MI/SO system-identification technique are presented. The corresponding numerical algorithm is then developed and applied to the experimental data of the MDOF system using only the subharmonic motion responses to identify the system parameters. The resulting model is then employed in Part 2 for a detailed analysis of both the sub and superharmonic dynamic behavior of the MDOF experimental system and a comparison of the MDOF response results and observations with those of the corresponding SDOF system examined earlier by the authors.

1.
Edwins
,
P. J.
, 1984,
Model Testing: Theory and Practice
,
Research Studies
, Letchworth, Hertordshire, England.
2.
Rice
,
H. J.
, and
Fitzpatrick
,
J. A.
, 1991, “
The Measurement of Nonlinear Damping on Single Degree-of-Freedom System. Transaction of the American Society of Mechanical Engineers
,”
Trans. ASME, J. Vib. Acoust.
1048-9002,
113
, pp.
132
140
.
3.
Rice
,
H. J.
, and
Fitzpatrick
,
J. A.
, 1988, “
A Generalized Technique for Spatial Analysis of Non-Linearization
,”
Mech. Syst. Signal Process.
0888-3270,
2
, pp.
195
207
.
4.
Bendat
,
J. S.
,
Palo
,
P. A.
, and
Coppolino
,
R. N.
, 1992, “
A General Identification Technique for Nonlinear Differential Equations of Motion
,”
Probab. Eng. Mech.
0266-8920,
7
, pp.
43
61
.
5.
Bendat
,
J. S.
, and
Piersol
,
A. G.
, 1993,
Engineering Applications of Correlation and Spectral Analysis
,
Wiley
, New York.
6.
Narayanan
,
S.
,
Yim
,
S. C. S.
, and
Palo
,
P. A.
, 1998, “
Nonlinear System Identification of a Moored Structural Systems
,”
Proceedings of the 18th International Offshore and Polar Engineering Conference
,
Montreal
, Canada, May 24–29 1998, Vol.
III
, pp.
478
484
.
7.
Narayanan
,
S.
, and
Yim
,
S. C. S.
, 2000, “
Nonlinear Model Evaluation via System Identification of a Moored Structural System
,”
Proceedings of the 10th International Offshore and Polar Engineering Conference
,
Seattle
, USA, 28 May–2 June 2000, Vol.
III
, pp.
403
409
.
8.
Panneer Selvam
,
R.
, and
Bhattacharyya
,
S. K.
, 2001, “
Parameter Identification of a Compliant Nonlinear SDOF System in Random Ocean Waves by Reverse-MISO Method
,”
IEEE J. Ocean. Eng.
0364-9059,
28
, pp.
1199
1223
.
9.
Niedzwecki
,
J. M.
, and
Liagre
,
P. Y. F.
, 2003, “
System Identification of Distributed-Parameter Marine Riser Models
,”
IEEE J. Ocean. Eng.
0364-9059,
30
, pp.
1387
1415
.
10.
Liagre
,
P. F.
, and
Niedzwecki
,
J. M.
, 2003, “
Estimating Nonlinear Coupled Frequency-Dependent Parameters in Offshore Engineering
,”
Appl. Ocean. Res.
0141-1187,
25
, pp.
1
19
.
11.
Naraynan
,
S.
, and
Yim
,
S. C. S.
, 2004, “
Modeling and Identification of a Nonlinear SDOF Moored Structure, Part I, Hydrodynamic Models and Algorithm
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
126
, pp.
175
182
.
12.
Yim
,
S. C. S.
, and
Narayanan
,
S.
, 2004, “
Modeling and Identification of a Nonlinear SDOF Moored Structure, Part II, Comparisons and Sensitivity Study
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
126
, pp.
183
190
.
13.
Lin
,
H.
, and
Yim
,
S. C. S.
, 2005, “
An IFF Model for a SDOF Nonlinear Structural System, Part I: Modeling and Comparisons
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219 (in press).
14.
Yim
,
S. C. S.
, and
Lin
,
H.
, 2005, “
An IFF Model for a SDOF Nonlinear Structural System, Part II: Analysis of Complex Responses
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219 (in press).
15.
Wang
,
C. Y.
, 1965, “
The Flow Induced by an Oscillating Sphere
,”
J. Sound Vib.
0022-460X,
2
, pp.
257
267
.
16.
Hjelmfelt
,
A. J.
,
Carney
,
J. F.
, III
,
Lee
,
S. L.
, and
Mockros
,
L. F.
, 1967, “
Dynamic Response of a Restrained sphere in a Fluid
,”
J. Eng. Mech. Div.
0044-7951,
93
, pp.
41
56
.
17.
Harleman
,
D. R. F.
, and
Shapiro
,
W. C.
, 1958, “
Investigations on the Dynamics of Moored Structures in Waves
,” M.I.T. Hydrodynamics Lab. Tech. Report No. 28.
18.
Grace
,
R. A.
, and
Casiano
,
F. M.
, 1969, “
Ocean Wave Forces on a Sub Surface Sphere
,”
J. Waterw. Harbors Div., Am. Soc. Civ. Eng.
0044-8028,
95
, pp.
291
312
.
19.
Grace
,
R. A.
, and
Zee
,
G. T. Y.
, 1978, “
Further Tests on Ocean Wave Forces on Sphere
,”
J. Waterw., Port, Coastal, Ocean Div., Am. Soc. Civ. Eng.
0148-9895,
104
, pp.
83
88
.
20.
Yim
,
S. C. S.
,
Myrum
,
M. A.
,
Gottlieb
,
O.
,
Lin
,
H.
, and
Shih
,
I.-M.
, 1993, “
Summary and Preliminary Analysis of Nonlinear Oscillations in a Submerged Mooring System Experiment
,” Ocean Engineering Report No. OE-93-03, Office of Naval Research.
21.
Lin
,
H.
, 1994, “
Stochastic Analysis of a Nonlinear Ocean Structural System
,” Ph.D. dissertation. Oregon State University.
22.
Gottlieb
,
O.
, and
Yim
,
S. C. S.
, 1992, “
Nonlinear Oscillations, Bifurcations, and Chaos in a Multi-Point Mooring System
,”
Appl. Ocean. Res.
0141-1187,
14
(
6
), pp.
241
257
.
23.
Narayanan
,
S.
, 1999, “
Experimental Analysis of a Nonlinear Moored Structure
,” Ph.D. dissertation, Oregon State University.
24.
Chakrabarti
,
S. K.
, 1987,
Hydrodynamics of Offshore Structures
,
Computational Mechanics Publications
, London.
25.
Bendat
,
J. S.
, 1998,
Nonlinear System Techniques and Application
,
Wiley
, New York.
26.
Clough
,
R. W.
, and
Penzien
,
J.
, 1993,
Dynamics of Structures
,
McGraw-Hill
, New York.
27.
Gerald
,
G. F.
, and
Wheatley
,
P. O.
, 1989,
Applied Numerical Analysis
,
Addison-Wesley
, New York.
28.
MATLAB 6.5.1,
The MathWorks, Inc.
, 1994–2004.
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