Method for calculating ship parameter-strength excited rolling response probability under random sea conditions

A strong incentive and ship technology, applied in the field of transportation and information, can solve the problem of uncertain ship wave conditions

Inactive Publication Date: 2017-10-17
TIANJIN UNIV
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Problems solved by technology

However, for real random sea conditions, we cannot determine the specific wave conditions encountered by the ship after going out to sea, so the time history curve of the parametric-strongly excited roll response of a purely numerical simulation ship under a certain set of random seed numbers does not have much significance. The inventors pay more attention to the statistical characteristics of the ship’s roll response under random parameter-strong excitation, that is, to predict the response probability distribution of the ship

Method used

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  • Method for calculating ship parameter-strength excited rolling response probability under random sea conditions
  • Method for calculating ship parameter-strength excited rolling response probability under random sea conditions
  • Method for calculating ship parameter-strength excited rolling response probability under random sea conditions

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Embodiment Construction

[0053] The present invention will be described in detail below

[0054] 1. Establish the ship's parametric-strong excitation single degree of freedom rolling motion equation, that is, the mathematical vibration equation.

[0055]

[0056] Among them, Φ is the roll angle; I xx Is the rolling moment of inertia, A xx (ω n ) Is the additional moment of inertia for rolling; b 1 With b 3 They are linear damping coefficient and cubic nonlinear damping coefficient; Δ is displacement; g is gravitational acceleration; GZ is the ship's righting arm, which is determined by Φ, η and Ψ; M is the wave forced excitation moment.

[0057] In a fixed coordinate system, the waveform expression of a long peak wave whose wavelength is equal to the ship length along the x-axis at a certain moment is ηcos(2πx / L+Ψ), where η is the wave amplitude of the long peak wave (η>0 is The crest, η<0 is the trough), Ψ is the relative position of the ship and the wave, and the value range is [0-2π].

[0058] 2. Solve the...

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Abstract

The invention relates to a method for calculating a ship parameter-strength excited rolling response probability under random sea conditions. The method comprises the steps that a ship parameter-strength excited single-freedom-degree rolling motion equation, namely a mathematical vibration equation is established; a function for solving a ship righting arm based on a slice theory is established and used for obtaining the ship righting arm in the mathematical vibration equation; a wave surface angle is utilized to solve a random wave forced excitation moment used for obtaining the wave forced excitation moment in the mathematical vibration equation; a spectral analysis method is adopted to process the random sea conditions and used for obtaining random excitation items in the mathematical vibration equation; and an energy envelope random averaging method is adopted to solve the mathematical vibration equation to obtain probability distribution of ship rolling responses.

Description

Technical field [0001] The invention belongs to the technical fields of transportation, information, etc., and relates to the prediction of the motion response of a ship under real random sea conditions. Background technique [0002] At present, as maritime transport ships are increasingly developing in the direction of large-scale, high-tech, and high-performance, the integrity and stability requirements have become an important foundation for ensuring the safety of ships, as well as mandatory statutory requirements for ship design and construction. As we all know, cross winds and waves are extremely dangerous sea conditions for ships to navigate, and the swaying motion of ships in these sea conditions is the main cause of ship capsizing. People have been focusing on this problem for a long time, and so far, a large number of and in-depth research results have been obtained for it. However, through the observation and statistics of complete ship accidents, the results show that...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50G06F17/11B63B9/00
CPCB63B71/10G06F17/11G06F30/20
Inventor 刘利琴刘亚柳李妍王丽元
Owner TIANJIN UNIV
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