Stability Calculation In Bulk Carrier Loading Computer

Ship floating condition and stability calculation are core algorithms of bulk carrier loading computer.To improve calculation accuracy,this paper studies the core algorithms based on the 3D model of bulk carrier's hull and all compartments.The following works were carried out:(1)Ship's hull model database was established on the basis of ship's 3D design model.First,the moulded data in each frame was obtained through slicing 3D design surface longitudinally using the slicing module in CGAL(Computational Geometry Algorithms Library);Then,the hull data were gained by equidistant offsetting of transverse moulded data,which simulated the hull thickness.(2)Based on hull database,ship floating condition in arbitrary loading condition was calculated.First,The Jacobi matrix coefficients were achieved by intersecting water plane and hull data;Then,ship floating condition equations were solved by using Newton iteration method.The computational error between calculated results and those given by the loading manual was relatively small.Compared with traditional methods,this method can be used to calculate arbitrary floating conditions in real-time with high precision.(3)Righting arms were calculated using different intact stability methods and the curves of righting arm under different loading conditions were plotted.Results showed that the computation using static equilibrium method had the smallest error compared with NAPA's computational results,which verified the accuracy and feasibility of using 3D design data to calculate ship stability.(4)Parallel accelerate process in ship floating condition and stability calculation was realized by using GPU(Graphics Processing Unit).The Jacobi matrix coefficients were achieved by intersecting water plane and hull data in GPU.Results showed that a speedup of 6 to 10 times could be attained and that the computational performance was improved effectively.In this thesis,all the examples were carried on using the C++ programming.The accuracy of the algorithm was verified by comparison with the loading manual.The algorithm was integrated in the bulk carrier loading computer and installed in real ships.