Response Analysis of Floating Structures

The dynamic response of a floating structure may be obtained either by analyzing the complete fluid-structure system or by a simpler method, in which the hydrodynamic effects are accounted for by the inclusion of added mass. Since the added mass of a floating structure is dependent on the frequency of its oscillation, the traditional use of a constant added mass is large over the frequency range of interest. Such a situation may arise when the floating body is acted upon by transient loads or when the body is enclosed in a basin having resonant frequencies, or both. A method to construct an equivalent model for the fluid-structure system in such cases, for the time domain response analysis of the floating structure, is presented in this paper. For construction of this model the frequency dependence of the added mass is assumed to be known.