Method for determining marine riser VIV fatigue safety factor based on reliability

A determination method and technology of safety factor, applied in the field of determination of marine riser vortex-induced vibration fatigue safety factor, can solve problems such as fatigue and inability to accurately evaluate VIV fatigue strength, and achieve the effect of reducing the possibility

Active Publication Date: 2018-09-28
ZHEJIANG UNIV OF TECH +1
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Problems solved by technology

[0003] In order to overcome the deficiency that the existing technology cannot accurately evaluate the VIV fatigue strength of the marine riser, the present invention provides a method for determining the VIV fatigue safety factor of the marine riser based on reliability, which can effectively determine the safety of the VIV fatigue of the marine riser. Coefficient, guiding the design of marine riser VIV fatigue, reducing the possibility of marine riser VIV fatigue damage

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  • Method for determining marine riser VIV fatigue safety factor based on reliability
  • Method for determining marine riser VIV fatigue safety factor based on reliability
  • Method for determining marine riser VIV fatigue safety factor based on reliability

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Embodiment Construction

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] refer to figure 1 , a method for determining the VIV fatigue safety factor of marine risers based on reliability, including the following steps:

[0031] Step S1, constructing the VIV fatigue limit state equation in logarithmic form;

[0032] Step S2, determining random variables that affect VIV fatigue damage;

[0033] Step S3, constructing the response surface of the fatigue damage of each random variable, and calculating the partial derivative of the fatigue damage to each random variable;

[0034] Step S4, using the first-order second-order moment method to obtain the expression of the reliability index;

[0035] Step S5, obtaining the target reliability index of the total life from the annual failure probability;

[0036] Step S6, deriving the fatigue safety factor formula of VIV fatigue.

[0037] Further, in the step S1, the logarithmic limit state eq...

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Abstract

A method for determining marine riser VIV fatigue safety factor based on reliability is provided. The method comprises: constructing a VIV fatigue damage limit state equation in a logarithmic form; determining random variables affecting VIV fatigue damage; constructing a response surface of fatigue damage for each random variable, and calculating the partial derivative of fatigue damage to each random variable; using the second-order moment method to obtain an expression of the riser VIV fatigue reliability index; obtaining the target reliability index of the total life of the riser from the annual failure probability; deriving a VIV fatigue safety factor formula; and giving a calculation flow and examples. The method provided by the present invention can be used to guide the design and evaluation of marine riser VIV fatigue strength.

Description

technical field [0001] The invention belongs to the field of marine engineering design, and relates to the VIV fatigue strength design and evaluation of marine risers, in particular to a reliability-based method for determining the fatigue safety factor of vortex induced vibration (Vortex Induced Vibration hereinafter referred to as VIV) of marine risers. Background technique [0002] The VIV fatigue life of risers is difficult to accurately estimate for the following reasons. One is that the vortex-induced vibration response during service is mainly determined by the floating body motion and viscous fluid load in the complex ocean environment, and its load is difficult to predict accurately; the other is the calculation model of fatigue life, including the S-N curve and the Miner linear accumulation method. There is also some uncertainty. In the current code, in order to ensure the design life of the riser, for all kinds of traditional forms of floating body-riser systems,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/20G06F2113/14G06F2119/04
Inventor 吴剑国李智博张国进张萌万子诚孙政策
Owner ZHEJIANG UNIV OF TECH
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