Comparison of linear and nonlinear responses of a compliant tower to random wave forces

Han, Seon; Benaroya, Haym

doi:10.1016/s0960-0779(01)00232-6

Cited by 10 publications

(10 citation statements)

References 12 publications

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“…The wave height is assumed small compared to the wavelength and water depth. In line with this, the flow potential and fluid particle velocities in equations (17) and (18) are solved for the wave kinematics subject to the boundary conditions at the water surface and at the bottom of the platform.…”

Section: Governing Equations Of the Wave Theorymentioning

confidence: 99%

“…The results are compared with the model laboratory work which shows minimal difference for surge and sway degree of freedoms; heave response of the simulation is smaller than the laboratory, and there are some differences in tendon tension for the two approaches. Han and Benaroya 17 formulated coupled nonlinear equation for axial and transverse motion of a tower. The nonlinear free and forced responses are later compared with the linear model.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of tendon dynamics effects on tension leg platform response in random seas

Oyejobi

Jameel

Sulong

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part M:

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This study investigated tendon dynamics effects of tension leg platform models with tendons modelled by finite element spring and beam elements for uncoupled and coupled tension leg platform in random waves and current environment. The purpose of the study is to proffering numerical solution of single mathematical equation of motion for fully integrated-coupled tension leg platform floater with tendons model. Structural modelling of complete tension leg platform is achieved with the help of ABAQUS/Standard finite element tools which is incorporated with ABAQUS/Aqua module for the application of hydrodynamic loadings on the partially submerged tension leg platform hull and fully submerged platform tendons. For the uncoupled tension leg platform model, weight, inertia, hydrodynamic force and damping forces are ignored on the tendons modelled with springs, while the stiffness of the tendons is considered as a static restoring force. The coupled tension leg platform model had all the forces applied on the tendons modelled with beam elements. Conclusively, modelling and analysis of the tension leg platform as uncoupled and coupled models have expanded our understanding to know that surge motion response is fairly predicted by the two models, however, heave and pitch motions, and variations in tendon tension differ significantly; hence, coupled tension leg platform model is recommended. The influence of a removed tendon due to accident or maintenance on the tension leg platform motions is also reported.

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Section: Governing Equations Of the Wave Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of tendon dynamics effects on tension leg platform response in random seas

Oyejobi

Jameel

Sulong

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part M:

View full text Add to dashboard Cite

show abstract

“…Based on the concepts of equivalent linearization and a time averaging method they obtained the maximum stress. Han and Benaroya [15,16] developed a nonlinear model for the coupling axial and transverse displacements of tendons of a TLP. A comparison of linear and nonlinear responses to random wave forces was obtained by a numerical method in the time domain.…”

Section: Introductionmentioning

confidence: 99%

Dynamic response of a deepwater riser subjected to combined axial and transverse excitation by the nonlinear coupled model

Song

Zheng

Kennedy

2017

International Journal of Non-Linear Mechanics

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In offshore engineering long slender risers are simultaneously subjected to both axial and transverse excitations. The axial load is the fluctuating top tension which is induced by the floater's heave motion, while the transverse excitation comes from environmental loads such as waves. As the time-varying axial load may trigger classical parametric resonance, dynamic analysis of a deepwater riser with combined axial and transverse excitations becomes more complex. In this study, to fully capture the coupling effect between the planar axial and transverse vibrations, the nonlinear coupled equations of a riser's dynamic motion are formulated and then solved by the central difference method in the time domain. For comparison, numerical simulations are carried out for both linear and nonlinear models. The results show that the transverse displacements predicted by both models are similar to each other when only the random transverse excitation is applied. However, when the combined axial dynamic tension and transverse wave forces are both considered, the linear model underestimates the response because it ignores the coupling effect. Thus the coupled model is more appropriate for deep water. It is also found that the axial excitation can significantly increase the riser's transverse response and hence the bending stress, especially for cases when the time-varying tension is located at the classical parametric resonance region. Such time-varying effects should be taken into account in fatigue safety assessment.

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“…Furthermore, they concluded that the coupled model at a lower load yields an unstable behavior in comparison of the uncoupled model. Han and Benaroya (2002) modeled a vertical member of compliant offshore structure as a beam which is undergoing bending and extension. Also the beam has a point mass and is subjected to an axial load at the free end.…”

Section: Introductionmentioning

confidence: 99%

TLP Structural Health Monitoring Based on Vibration Signal of Energy Harvesting System

Jahangiri

Mirab

Fathi

et al. 2016

Lat. Am. j. solids struct.

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Structural Health Monitoring (SHM) of Tension Leg Platform (TLP) is very crucial for preventing catastrophic and sudden collapse of the structures. One of the methods of monitoring these structures is implementing SHM sensors. Supplying energy for these sensors for a long period is a challenging problem. So, one of the new methods of supplying energy for SHM, is usage of mechanical energy. In this method, the piezoelectric material is employed to convert the mechanical energy which is resulted from vibration of structure, to electrical energy. The advantage of this method is based on not implementing the battery charging system. Therefore, in this paper, after modeling TLP structure, energy supplying of these sensors with piezoelectric converters is studied. Furthermore, fault diagnosis of these structures in the presence of different uncertainties is proposed by the features of voltage signal, produced from piezoelectric patches and fuzzy classification method. Results show that this method can diagnose faults of the structure with an acceptable success rate.

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Comparison of linear and nonlinear responses of a compliant tower to random wave forces

Cited by 10 publications

References 12 publications

Investigation of tendon dynamics effects on tension leg platform response in random seas

Investigation of tendon dynamics effects on tension leg platform response in random seas

Dynamic response of a deepwater riser subjected to combined axial and transverse excitation by the nonlinear coupled model

TLP Structural Health Monitoring Based on Vibration Signal of Energy Harvesting System

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