Effect Of Different Configuration Of Connectors On Dynamic Characteristics Of Floating Platform

As land resource increasingly exthausted,utilization of ocean space has been desired,Very Large Floating Structure(VLFS)is a state-of-art marine equipment,and attracts the much attention of researchers from worldwide.Thus they have put a great deal of efforts in studying VLFS.Supper scale floating platform,consisting of multiple modules flexibly connected by connectors,is a nonlinear nonautonomous system with hydroelastyic coupling effect in waves.The network theory is employed in the investigation of dynamic characteristics of VLFS in this thesis.This thesis presents a study of virtual prototype model of multi-modular VLFS using software ADAMS,based on the linear wave theory,mooring system model and a single floating body dynamic model.Using the software ADAMS can quickly build the structure model and simulate the dynamic behaviors without involving complex mathematical derivation of the connector model.In addition we can easily parameterize the simulation model of VLFS.It is convenient to modify the prototype model of floating platforms with the benefit of visualization.This thesis reports an investigation on five types of connector models,namely parallel articulated connector,middle articulated cross connector,middle articulated composite connector,cross connector and composited connector.Using software ADAMS in numerical simulations,we study the load characteristics of five kinds of connectors and the nonlinear response of chained pontoon type floating structures.Further the studies extend to the jumping response of the floating structure,the phenomenon of Amplitude Death as well as the network synergatic effect among the modules.The phenomenon of Amplitude Death is a state that the floating modules collectively tend to a weak oscillatory state under wave excitation,an important concept for system stability.Since the wave period and connector stiffness are important factors in determination of the stability of the floating platform,the design parameteric space associated with Amplitude Death state is investigated in a span of connector stiffness and wave period.The larger area of Amplitude Death leads to better stability of the floating platform.Based on the concept of the Amplitude Death,a comparison study on the five kinds of connectors is conducted,and the results indicate that the composited connector is the best option in terms of the system stability.