Mooring power truncation simulation method based on energy spectrum

Abstract

The invention discloses a mooring power truncation simulation method based on an energy spectrum, and belongs to the technical field of oceanographic engineering simulation test. The method comprisesthe steps: applying irregular motion excitation to the top of a mooring line, and obtaining a mooring force in a time domain through a nonlinear power response model of the mooring line; extending theperturbation of the mooring force to the frequency domain through a fast Fourier transform algorithm to form a mooring energy spectrum; building a multi-target optimization function through the energy corresponding to a finite number of frequency points selected from the energy spectrum according to one weight, and performing solving and calculation to obtain a mooring line parameter result meeting the power truncation optimization requirements. In the method, the nonlinear features of the dragging force and inertia force of the mooring line are completely maintained in the time domain, and the peak values and frequency of the features are also maintained to the maximum degree after the features are converted to the frequency domain, thereby effectively guaranteeing the similar power response before and after truncation. In addition, the number of optimization variables is smaller, thereby solving a problem that the time-step by time-step contrast in the complete time domain consumesa large amount of time and a credible solution cannot be found.

Description

technical field [0001] The invention belongs to the technical field of ocean engineering model tests, and in particular relates to a mooring power truncation simulation method based on energy spectrum. Background technique [0002] In order to accurately predict the motion response of the deep-sea platform in deep-sea operation and to ensure the stability of the offshore platform operation, it is necessary to adopt the method of model test. The method of model test needs to adopt the conventional scale ratio method and follow the Froude similarity criterion. However, the size of existing marine engineering tanks is limited, and model tests cannot be carried out within a reasonable scale. In order to effectively solve the problem of deep-water model tests and make full use of the depth of existing pools, a passive hybrid model test method is widely used at present. The most important part in the passive hybrid model test is the truncation design of the mooring system, and th...

AI Technical Summary

Problems solved by technology

This method satisfies the technical problem of dynamic similarity in the equivalent truncation of the passive mooring model test, and solves the problem that the time-step comparison in the complete time domain takes a lot of time and cannot find a credible solution

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