Strength Analysis And Optimization Of Ship Hull Structure For The Integrated Transport And Installation Of Offshore Wind Turbine

In order to cope with the energy crisis, all countries, are a positive development in wind power and vigorously carry out the construction of offshore wind farms which is an important measure to us, a big energy consuming country, in recent years. The installation of wind power transportation is the major equipment for the construction of an offshore wind farm. The new vessel of wind power integrated transport installation is another type of marine engineering ship. In difference with the integral lifting crane and self-elevating split installation platform, this modern ship set overall transportation and installation of an in one. Without cooperating with other ships, it completes fine overall transportation and hoisting work high efficiently and accurately, reduces the time for maritime operations, and decreases security risks. Integrated transportation and installation of turbines have used to be part of the trend in the development of wind power installation in the future.Overall and structure designs are expected to be completed in the integrated transport and installation of wind power which can simultaneously transport four 6MW wind turbines in this paper. Taking into account the enormous tonnage of fans, the concentrated position, and the need for long distance longitudinal movement of the vessel’s deck, the structural strength of the ship, especially the total longitudinal strength is the focus of research. The main work and research results are as follows:(1) According to the functional requirements of the ship, profile design and layout design are completed and a brief introduction is provided in the paper. The floating state is adjusted depending on unique conditions.(2) Of the current, the research and specification about integrated transport wind power installation ship are not much, and the intensity analysis specification has not yet been introduced. In this paper, a set of exact calculation method for the strength of the entire ship in the integrated transport and installation of wind power is summarized, referring to the “CCS Guidelines for Direct Strength ship structure” and other relevant documents. It gives very detail describes in Modelling Rules, Load Calculation Methoda, design wave parameter determination method, boundary conditions Selection Method and allowable stress requirements.(3) Wave load prediction is based on the design wave method. Panel Model and mass model are built by using SESAM PatranPre, while Amidships sectional vertical wave bending moment of the transfer function in eight working conditions is achieved by SESAM. The research combines wave spectrum Pierson-Moskowitz with Weibull distribution making a long-term forecast. Utilizing the results, it calculates the design wave length parameter, wave amplitude parameter, and so on. It also covers that predict the wave loads making use of the HydroD module in SESAM.(4) The research analyses the longitudinal strength of the ship hull. It determines the structural arrangements of the ship referring to "CCS steel ship classification rules", reads the results of hydrodynamic loads by the PCL language and the function of the FEM field, and applies Hydrodynamic load to finite element model of the ship by using the linear extrapolation method. The "inertial release" function of Nastran is used for boundary conditions. The calculation results show that the high stress level in the ship sailing condition is mainly concentrated in the base of the wind turbine, and that in the working condition is concentrated near the truss of tail wind turbine and beneath the fan base, which is due to the large tonnage of the fan.(5) For the ship structure near the base of the wind turbine, it uses Optimize for MSC. Patran/Nastran function to select the appropriate variable, within the constraint that the synthetic stress is not more than the allowable stress, optimizing size that aims to lightest. It proceeds to an analysis of the optimized model of a working condition, which shows that the altered structure size can effectively reduce structural stress level and reduce structural weight.