Modeling and Identification of a Nonlinear SDOF Moored Structure, Part 1—Hydrodynamic Models and Algorithms
- 1 May 2004
- journal article
- Published by ASME International in Journal of Offshore Mechanics and Arctic Engineering
- Vol. 126 (2), 175-182
- https://doi.org/10.1115/1.1710875
Abstract
The highly nonlinear responses of compliant ocean structures characterized by a large-geometry restoring force and coupled fluid-structure interaction excitation are of great interest to ocean and coastal engineers. Practical modeling, parameter identification, and incorporation of the inherent nonlinear dynamics in the design of these systems are essential and challenging. The general approach of a nonlinear system technique using very simple models has been presented in the literature by Bendat. In Part 1 of this two-part study, two specific nonlinear small-body hydrodynamic Morison type formulations: (A) with a relative-velocity (RV) model, and (B) with an independent flow-field (IFF) model, are formulated. Their associated nonlinear system-identification algorithms based on the reverse multiple-input/single-output (R-MI/SO) system-identification technique: (A.1) nonlinear-structure linearly damped, and (A.2) nonlinear-structure coupled hydrodynamically damped for the RV model, and (B.1) nonlinear-structure nonlinearly damped for the IFF model, are developed for a specific experimental submerged-sphere mooring system under ocean waves exhibiting such highly nonlinear response behaviors. In Part 2, using the measured input wave and output system response data, the algorithms derived based on the MI/SO linear analysis of the reverse dynamic systems are applied to identify the properties of the highly nonlinear system. Practical issues on the application of the R-MI/SO technique based on limited available experimental data are addressed.Keywords
This publication has 7 references indexed in Scilit:
- Experimental Calibration of Bifurcation Superstructure of Nonlinear SystemJournal of Engineering Mechanics, 1998
- Noisy Nonlinear Motions of Moored System. Part I: Analysis and SimulationsJournal of Waterway, Port, Coastal, and Ocean Engineering, 1997
- Thermomechanical Postbuckling of Stiffened Laminated Cylindrical ShellJournal of Engineering Mechanics, 1997
- Analysis of a Nonlinear System Exhibiting Chaotic, Noisy Chaotic, and Random BehaviorsJournal of Applied Mechanics, 1996
- Drag-induced instabilities and chaos in mooring systemsOcean Engineering, 1993
- A general identification technique for nonlinear differential equations of motionProbabilistic Engineering Mechanics, 1992
- The Onset of Chaotic Motions of a Moored Semi-SubmersibleJournal of Offshore Mechanics and Arctic Engineering, 1988