| The calculation of ship’s floating state stability is one of the core algorithms in the loading computer of bulk carrier.In order to improve the calculation accuracy,based on the ship’s three-dimensional body data,the cross section with multiple rings is fused to perform the stability calculation method.While ensuring the calculation accuracy,it improves the calculation efficiency and optimizes the polygon cropping algorithm in the calculation of ship floating and stability.This method not only ensures the calculation accuracy,but also optimizes the calculation efficiency,which provides a new idea for the calculation of the floating state and stability in bulk carrier loading computer.The main work is as follows:(1)The densitified table of offsets provided by the ship design department was studied.After comparing and analyzing each data table,it was preprocessed by using programming language to identify and read it.Then according to the relationship between the metadata,a high-precision ship 3D database was established and visualized to verify the accuracy and integrity of the data in the database.(2)The calculation model of free floating state of ship based on the densitified table of offsets was established,and the slicing method of height alignment and vertical stretching was proposed.Based on the proposed slicing method,a mathematical model is designed to calculate the displacement volume,center of buoyancy and geometric elements of waterline surface of ship in any floating state.Then,an example calculation was carried out,and the calculation result is compared with the given value in the loading manual.The error was small and the versatility was good.Compared with the traditional slicing method,it can be applied to any floating state of ship and omits(3)In view of the shortcomings of iterative time-consuming in real-time ship arbitrary floating state calculation,the off-line floating state database was proposed to interpolate the floating state characteristics of ships under different loading states.The appropriate value interval was determined by analyzing the influence of the value interval of three parameters of the floating state on the interpolation results.And the offline ship floating state database based on the densitified table of offsets was designed and’ established.(4)Based on the real ship data of "MV-M" ship,this paper uses the offline ship floating database to calculate the ship’s floating state and complete stability under different conditions,including the metacentric height,the metacentric arm and the heeling angle.The calculation results show that the Newton iterative method using offline floating state data to solve the floating state parameters effectively reduces the calculation time of the algorithm,and the error is within the acceptable range.Thus,the accuracy and feasibility of the multi-loop fusion slicing method based on stability calculation and the offline ship floating state database in stability calculation are verified.All the calculation examples in this paper are implemented by C++programming,and the accuracy of the algorithm was verified by comparing with the calculation value in the loading manual.The algorithm in this paper is integrated into the ship loading computer to complete the real ship installation.It provides a new idea for the stability calculation of various types of ship loading computer. |
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