Nonlinear Hydroelastic Response Analysis Of The Multi-body Floating System In Shallow Water Waves

With the exploitation of offshore resources in various countries in the world,the application of various forms of multi-body floating systems(floating bridges,submerged floating tunnels,floating photovoltaic systems,etc.)have shown a promising prospect.These multi-body floating systems have the following characteristics: First,they are often located in coastal waters and are subjected to shallow water waves.Therefore,the hydrodynamic characteristics of the multi-body floating systems may have nonlinear characteristics and also will be affected by the inhomogeneous wave fields.Second,according to the structural forms and the application conditions of the multi-body floating systems,there exist problems related to moving loads and other structural nonlinear problems.Third,due to its large scale and flexible structure,obvious elastic deformation will be induced by wave loads and other complex loads.The hydroelastic responses of multi-body floating systems under the action of complex loads have important engineering meanings in the design process.In this paper,the nonlinearity and inhomogeneity of shallow water waves,the application range of the hydroelastic method,the interaction mechanism between waves and multi-body floating systems and the nonlinear problems are investigated.To reflect the nonlinear characteristics of shallow water waves,the second-order Stokes wave theory is introduced,and a wave spectrum transformation method is presented.The nonlinear wave spectrum can be obtained from the linear wave spectrum and the water depth.Related to the inhomogeneous waves,the evolution of waves in a sloped seabed is investigated and the wave correlations at different positions are discussed.In order to solve the problem of the application range of the hydroelastic method,the relationship and boundary between the quasi-static method and the hydroelastic method are presented.As for the interaction mechanism between waves and multi-body floating systems,as an example,the frequency-domain and time-domain methods for the hydroelastic response prediction of the pontoon-separated floating bridge are established to investigate its hydroelastic responses under complex loads.When it comes to the nonlinear problem during the interaction process between fluid and structures,a semi-immersed cylinder is taken as an example to discuss the influence of the overtopping phenomenon on its hydrodynamic performance.