Approximate methods for dynamic response of multi-module floating structures

Abstract

Two-dimensional and three-dimensional approximate hydroelasticity theories are used to predict the dynamic response of 5- and 16-module very large floating structures in regular waves. For the two-dimensional approach, strip theory is combined with a beam model of the structure to determine the dynamic response. However, the fluid forces from strip theory are augmented with ‘surge’ forces calculated from Morison's equation. For the three-dimensional approach, a rigid module, flexible connector structural model is used with fluid loading obtained with the three-dimensional double composite source distribution technique. Fluid-structure interaction effects are studied and connector moments are obtained. These approximate methods of hydroelastic analysis offer alternatives to the more computationally demanding, fully three-dimensional flexible module, flexible connector model in which linear potential theory is used.