A Time Domain Model to Predict Dynamic Response of Multiple Floating Bodies Connected With Hinges Based on the Kane Method

Abstract

A two-dimensional model to estimate the hydrodynamic response of hinged multiple floating body systems in the time domain is established based on the Kane method. The reduced Kane equations applicable to the dynamic response of multi-floating body system with hinges are first deduced. The issue of hinge constraint in the system is addressed by defining the corresponding generalized speeds as zeros, while the wave actions are considered based on the potential flow theory. Then the corresponding calculation program is developed prior to undertaking the model test. Verification of the Kane-based model and the veracity of the program developed is performed through a series of contrastive analyses on a hinged floating bridge in various cases including regular waves, moving loads, and their combinations. The predictions obtained by the proposed model show satisfactory agreements with the model test measurements. The related results indicate that the motion responses of the first pontoon are greatest in a hinged floating bridge, and its motion amplitudes descend nonlinearly with the increment of wave frequency. The time-history motion responses of hinged multi-floating bodies in the middle present saddle shapes with some fluctuations as a whole under the combined effect of wave and moving loads. The Kane-based model is convenient to analyze the dynamic characteristics of a hinged multi-floating body system in regular waves, and it could be further extended to consider the effects of irregular waves, inhomogeneous sea conditions, as well as the nonlinear connections on the system.