A Calculation Method of Ship's Arbitrary Floating State Based on STL Model

Abstract

The invention discloses a method for calculating a random floating state of a ship on the basis of an STL (Stereo Lithography) model. The method comprises the following steps of calculating a midship draft TM, a heeling angle tangent value tan(Theta) and a trimming angle tangent value of the ship according to a conventional method; determining an equation of an inclined waterplane according to the midship draft, a heeling angle and a trimming angle; calculating a ship body displacement volume V under the waterplane and buoyancy coordinates (XB, YB, ZB); calculating barycentric coordinates (X'G, YG', Z'G) and buoyancy center coordinates (X'B, YB', ZB') of the ship under a fixed coordinate system; judging whether floating state equations meet a balance condition or not; performing three-parameter iterative calculation according to a fore draft, an aft draft and the heeling angle if the floating state equations do not meet the balance condition. The invention provides a three-parameter iterative method for calculating the floating state of the ship under any loading condition on the basis of the STL model, which has the features that the transverse inclination and longitudinal inclination of the ship can be calculated simultaneously, the method is suitable for any floating state of the ship, and the calculation precision is improved. The method disclosed by the invention has the advantages that the calculation quantity is reduced, the displacement volume and buoyancy center of the ship under any floating state are only calculated, and a program is strong and stable.

Description

technical field [0001] The invention belongs to the field of ship performance calculation, in particular to a ship floating state calculation method. Background technique [0002] Calculation of the ship's floating state refers to the calculation of the midship draft T of the ship M , heel angle θ and pitch angle Ship bow draft T can also be used F , ship stern draft T A And the expression method of heel angle θ. The calculation of the floating state of the ship under any loading condition is an important prerequisite for the safe navigation of the ship, and it is also the basis for the calculation of the stability of the ship, the calculation of the shear force of the ship, the calculation of the bending moment of the ship, the automatic loading of the ship, the optimization of the ship loading process, and the determination of the loading and unloading sequence of the ship. In addition, during the loading process, the ship needs to be properly loaded so that the ship ...

AI Technical Summary

Problems solved by technology

[0029] From these assumptions, it can be seen that the conventional method is suitable for the calculation of small trim of the ship, and the error will increase when the trim is large, and it is not suitable for the case of large ship trim

[0030] (2) The second type of "matrix method" needs to calculate the Jacobian matrix including multiple elements such as waterplane area, buoyancy center, moment of inertia, drainage volume and buoyancy center in each iterative calculation. The formula expression is very cumbersome, and the calculation The workload is heavy. If the water plane is a special vessel such as a trimaran or pentamaran, it is difficult to process the program

However, they have a large number of iterations and slow convergence speed. Generally, hundreds to thousands of iterations are needed to find the optimal result, which is not suitable for real-time computing.

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