Least-Squares, Moment-Based, and Hybrid Polynomializations of Drag Forces
Publication: Journal of Engineering Mechanics
Volume 130, Issue 3
Abstract
In order to carry out nonlinear dynamic analyses of fixed offshore structures in the frequency domain, polynomial approximations of the distributed drag term, and inundation drag term, of the Morison forces are studied. The methods of least-squares and moment-based approximations are considered for cases with and without current. Numerical results and analytical expressions of the polynomial coefficients are presented for the cubic approximations of and quartic approximations of The curve shapes, first four central moments, and probability density functions of the different approximations are evaluated and compared with the corresponding exact solutions. For the nonmonotonic inundation drag term with the current effect included, a hybrid polynomialization, based on the least-squares approximation for the odd-order polynomial coefficients and the moment-based approximation for the even-order coefficients, is proposed.
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Information
Published In
Journal of Engineering Mechanics
Volume 130 • Issue 3 • March 2004
Pages: 294 - 302
Copyright
Copyright © 2004 American Society of Civil Engineers.
History
Received: Mar 27, 2002
Accepted: Aug 26, 2003
Published online: Feb 19, 2004
Published in print: Mar 2004
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