A reliability-based method for determining the wave-induced fatigue safety factor of marine risers

A determination method and technology of safety factor, which is applied in the field of determining the safety factor of wave-induced fatigue of marine risers, can solve problems such as the inability to evaluate the wave-induced fatigue life of risers, and achieve the effect of reducing the possibility

Active Publication Date: 2022-07-15
ZHEJIANG UNIV OF TECH +1
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Problems solved by technology

[0003] In order to overcome the inadequacy of existing technologies that cannot evaluate the wave-induced fatigue life of risers, the present invention provides a method for determining the safety factor of wave-induced fatigue of marine risers based on reliability, which can effectively determine the safety factor of wave-induced fatigue of marine risers , to guide the design of wave-induced fatigue of marine risers, and reduce the possibility of wave-induced fatigue damage of marine risers

Method used

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  • A reliability-based method for determining the wave-induced fatigue safety factor of marine risers
  • A reliability-based method for determining the wave-induced fatigue safety factor of marine risers
  • A reliability-based method for determining the wave-induced fatigue safety factor of marine risers

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Embodiment Construction

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] refer to figure 1 and figure 2 , a reliability-based method for determining the wave-induced fatigue safety factor of marine risers, the determination method comprising the following steps:

[0032] In step S1, a relational expression is introduced to construct a wave-induced fatigue limit state equation in logarithmic form;

[0033] Step S2, determining random variables affecting wave-induced fatigue damage;

[0034] Step S3, constructing the response surface of fatigue damage of each random variable, and calculating the partial derivative of fatigue damage to each random variable;

[0035] In step S4, the first-order second-moment method is used to obtain the expression of the reliability index;

[0036] Step S5, obtaining the target reliability index of the total life from the annual failure probability;

[0037] Step S6, derive the fatigue safety facto...

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Abstract

A reliability-based method for determining the wave-induced fatigue safety factor of marine risers. The relational expression is introduced to construct the wave-induced fatigue limit state equation in logarithmic form; the random variables affecting the wave-induced fatigue damage are determined; the fatigue of each random variable is constructed. The partial derivative of fatigue damage to each random variable is calculated based on the response surface of the damage; the first order second moment method is used to obtain the expression of the reliability index of the riser wave-induced fatigue; the target reliability index of the total life of the riser is obtained from the annual failure probability ;Finally deduce the safety factor formula of wave-induced fatigue; give the calculation process and examples. The present invention can be used to guide the design and evaluation of marine riser wave-induced fatigue strength.

Description

technical field [0001] The invention belongs to the field of marine engineering design, relates to the design and evaluation of the wave-induced fatigue strength of a marine riser, and in particular relates to a method for determining the wave-induced fatigue safety factor of a marine riser. Background technique [0002] The wave-induced fatigue life of the riser is difficult to estimate accurately for the following reasons. First, the dynamic response during service is mainly determined by the floating body motion and viscous fluid load in a complex marine environment, and its load is difficult to accurately predict; second, the calculation model of fatigue life, including the S-N curve and the Miner linear accumulation method, itself also exists certain uncertainty. In the current specification, in order to ensure the design life of the riser, for various traditional forms of floating body-riser system, for the three safety levels of low, medium and high, a relatively con...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/20G06F30/13G06F119/04
CPCG06F2119/04G06F30/20G06F30/13
Inventor 吴剑国李智博万子诚张萌张国进孙政策
Owner ZHEJIANG UNIV OF TECH
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