Analyzing method for parametric-excitation and vortex-induced vibratory fatigue of deep-ocean top tension riser

An analysis method and vibration fatigue technology, applied in vibration testing, measuring devices, testing of machine/structural components, etc., can solve problems such as unsafe analysis results and failure to consider the influence of parameter excitation.

Inactive Publication Date: 2013-10-16
TIANJIN UNIV
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Problems solved by technology

[0009] At present, the influence of parameter excitation is not considered in the vortex-

Method used

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  • Analyzing method for parametric-excitation and vortex-induced vibratory fatigue of deep-ocean top tension riser
  • Analyzing method for parametric-excitation and vortex-induced vibratory fatigue of deep-ocean top tension riser
  • Analyzing method for parametric-excitation and vortex-induced vibratory fatigue of deep-ocean top tension riser

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Embodiment Construction

[0048] A method for analyzing the fatigue of a deep-sea roof tension riser combined with parametric excitation and vortex excitation according to the present invention will be described in detail below with reference to the embodiments and the accompanying drawings.

[0049] figure 1 The theoretical flow chart of the deep-sea riser parametric-vortex induced combined vibration fatigue analysis method, figure 2 It is a schematic diagram of the combined parametric-vortex induced vibration model of a deep-sea top tension riser. Attached below figure 1 And attached figure 2 The technology of the present invention is described in detail.

[0050] Such as figure 2 As shown, platform 1 undergoes heave motion under the action of waves, which gives a displacement time-history response to the top of riser 2, causing the axial force of riser 2 to change time-varyingly with the movement of the buoyant body, thus acting as a parameter to excite the lateral vibration of riser 2 have ...

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Abstract

The invention provides an analyzing method for parametric-excitation and vortex-induced vibratory fatigue of a deep-ocean top tension riser. The analyzing method comprises 1) taking regard of vortex induced lift caused by ocean current and parametric excitation caused by platform heave, and establishing a parametric-excitation and vortex-induced vibration model for the riser; 2) calculating heaving movement of a platform under wave effects according to on-site measuring results or a numerical method, and determining the parametric excitation of the riser; 3) analyzing stability of the parametric excitation of the riser, and ensuring that the parametric excitation of the riser is within a stable range; 4) calculating parametric-excitation and vortex-induced vibration response of the riser, and obtaining a time-history stress curve for each point of the riser; 5) calculating a stress cycle index of each point of the riser in a rain-flow counting method; and 6) calculating a fatigue life of the riser via a Miner damage cumulating theory and an S-N curve method. The analyzing method of the invention overcomes the disadvantage that present fatigue analysis based on vortex induced vibration tends to be unsafe, and enables fatigue damage analysis of the riser to satisfy practicality better.

Description

technical field [0001] The invention relates to a deep-sea riser design and safety assessment method. In particular, it relates to a fatigue analysis method of parametric-vortex-induced combined vibration of a deep-sea top tension riser. Background technique [0002] With the increasing demand for oil and gas resources, offshore oil and gas exploitation is gradually developing from shallow sea to deep sea. As a channel connecting the sea surface and the seabed, the riser is used for exploration, drilling and liquid infusion, and is an essential key equipment in deep sea development. Top tension risers are mainly used in deep-sea platforms such as semi-submersible or Spar. A key issue in the design process is to conduct a reasonable analysis of the fatigue damage of the riser, and then use it to estimate the service life of the riser. According to different incentives, the current research on riser fatigue damage can be divided into three situations: [0003] (1) Vortex-in...

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Application Information

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IPC IPC(8): G01M7/02
Inventor 唐友刚张杰刘利琴张若瑜
Owner TIANJIN UNIV
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