Nonlinear dynamics and impact load in float-over installation

Zhihuan Hu, Xin Li, Wenhua Zhao, Xiao Wu

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A time-domain 3 Degrees of Freedom model is developed to investigate nonlinear dynamics and impact loads during float-over installations, which generally involve multi-body interactions between wave-induced vessel motions and nonlinear constraint components. By replacing the time-consuming convolution in calculating the retardation function, a more efficient method, i.e. state-space model, is applied to evaluate part of the radiation force. The established model, incorporating the multi-body interactions, is applied to study the nonlinear impact on Leg Mating Unit (LMU) by considering the sway, heave and roll motions of the float-over system. The structural characteristics are considered when modelling the characteristics of LMU. The dynamic behaviors of a given system is investigated in the form of bifurcation diagrams, along with impact map, amplitude spectrum and power spectral density (PSD). It is found that bifurcation phenomena, or a large angle of docking cone could dominate the installation due to the increased impact loads.

Original languageEnglish
Pages (from-to)60-78
Number of pages19
JournalApplied Ocean Research
Volume65
DOIs
Publication statusPublished - 1 Apr 2017

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Loads (forces)
State space methods
Power spectral density
Degrees of freedom (mechanics)
Convolution
Cones
Radiation

Cite this

Hu, Zhihuan ; Li, Xin ; Zhao, Wenhua ; Wu, Xiao. / Nonlinear dynamics and impact load in float-over installation. In: Applied Ocean Research. 2017 ; Vol. 65. pp. 60-78.
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Nonlinear dynamics and impact load in float-over installation. / Hu, Zhihuan; Li, Xin; Zhao, Wenhua; Wu, Xiao.

In: Applied Ocean Research, Vol. 65, 01.04.2017, p. 60-78.

Research output: Contribution to journalArticle

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AU - Wu, Xiao

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AB - A time-domain 3 Degrees of Freedom model is developed to investigate nonlinear dynamics and impact loads during float-over installations, which generally involve multi-body interactions between wave-induced vessel motions and nonlinear constraint components. By replacing the time-consuming convolution in calculating the retardation function, a more efficient method, i.e. state-space model, is applied to evaluate part of the radiation force. The established model, incorporating the multi-body interactions, is applied to study the nonlinear impact on Leg Mating Unit (LMU) by considering the sway, heave and roll motions of the float-over system. The structural characteristics are considered when modelling the characteristics of LMU. The dynamic behaviors of a given system is investigated in the form of bifurcation diagrams, along with impact map, amplitude spectrum and power spectral density (PSD). It is found that bifurcation phenomena, or a large angle of docking cone could dominate the installation due to the increased impact loads.

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