Nonlinear identification and input-output representation of the modal dynamics of marine slender structures

• Published in: Journal of Offshore Mechanics and Arctic Engineering
• Main Authors: Xiros, NI, Chatjigeorgiou, IK
• Format: Article in Journal/Newspaper
• Language: English
• Published: ASME-AMER SOC MECHANICAL ENG 2007
• Subjects: Nonlinear Identification; Input Output; Engineering; Ocean; Mechanical; Dynamics; Galerkin methods; Mathematical models; Modal analysis; Numerical methods; Spectrum analysis; Axial motions; Marine slender structures; Modal dynamics; Transverse motions; Ocean structures; dynamic response; fixed structure; Galerkin method; modeling; spectral analysis; stability analysis; structural response; Arctic
• Online Access: http://dspace.lib.ntua.gr/handle/123456789/18206; https://doi.org/10.1115/1.2746391

The present work treats the problem of the dynamic behavior of a vertical slender structure subject to combined axial and transverse motions. The solution method is based on a Galerkin-type semi-analytical formulation. The responses to sinusoidal monochromatic excitation are assessed with respect to the significance of each mode and their spectral content. As a result, a reduced, yet nonlinear, lumped model for each one of the significant modes of the structure is generated. The parameters of these fixed-structure models can be determined systematically by two methods relying on the spectral analysis of the numerically calculated modal responses of the structure. The resulting models constitute an explicit input-output relationship between the imposed motions and the modes of the structure, useful for stability analysis, design and control. Copyright © 2007 by ASME.