Research On The Modeling And Simulation Of Floating Dock Systems

This topic comes from the design of a 80,000t floating dock automatic control systems,it is one of the topics for the project sub.The modeling and simulation of flaring dock systems which this thesis studies provide a theoretical basis for the project and simulation support.As important and critical tools of large ship building, floating docks possess the prominent feature that vessels to be maintained or repaired could be accessed flexibly and manoeuvrably. Note that the efficiency and reliability of the floating dock lifting system would critically dominate the favorable working process of the whole floating dock system. However, traditional floating docks mainly adopt manual lifting systems, where not only sophisticated operation experience and high professional knowledge should be required but also low efficiency, large errors and other drawbacks would be induced. As a consequence, with the rapid development of computer and automatic control technologies, the design of floating dock automatic control systems would inevitably become a necessary trend.In order to enrich and enhance the study of floating dock systems, this thesis conducts deep studies and presents meaningful works focusing on the modeling and simulation of floating dock systems. Furthermore, the optimization models of ballast water quantity adjustment and corresponding time adjustment are deeply investigated, respectively. Consequently, an optimal ballast water adjustment strategy would be proposed by using abovementioned optimization models. Finally, simulation studies based on MATLAB are implemented on our proposed optimization models and adjustment strategy. Simulation results demonstrate that the resulting optimal adjustment strategy highly satisfies the demand for the floating dock design. Therefore, effective methods for the design of floating dock automatic control systems would be provided by the proposed investigations in this thesis. To be specific, the main works are as follows.Firstly, several state parameters, including trim, heeling and trimming angles, and hydrostatic curve, etc., of the floating dock are analytically computed. It should be noted that the computation for the hydrostatic curve of the floating dock is intensively studied in this thesis. Furthermore, the obtained state parameters and physical equations are used to build up the loading model for individual ballast tank of the floating dock. And, the penalty function method is utilized to solve the obtained loading model, from which the ballast water adjustment for each tank could be determined.Then, note that many floating docks are rebuilt from old vessels which result in irregular shapes and arrangements of dock hulls and ballast tanks, respectively. As a consequence, it is difficult to solve the loading model via traditional methods since the computing burden and procedures for the solution of the proposed model would become huge and complicated, respectively. In order to circumvent the abovementioned problems, we propose the optimization models of ballast water quantity adjustment and time for adjustment, respectively, based on the loading model in this thesis. The ballast water quantity adjustment and the corresponding time for valve opening could be obtained by solving these optimization models. And, the final adjustment strategy could be determined.Finally, a typical 80000-ton floating dock is adopted to demonstrate our proposed methods and strategies in this thesis. Simulation studies are implemented on the proposed optimization models by using MATLAB codes. Simulation results indicate that the whole adjustment strategy based on the optimization model could meet the demand for the design of floating docks.