Analytical Model for Ice-Structure Interaction

This paper presents a mathematical analysis of an extended model describing a sea ice-induced frequency lock-in for vertically sided offshore structures. A simple Euler-Bernoulli beam as model for the offshore structure is used, and a moving boundary between an ice floe and the structure itself is introduced. A nonlinear equation for the beam dynamics is found by using an asymptotical approach and a Galerkin procedure. It is shown analytically that a frequency lockin regime occurs during ice-induced vibrations (IIV), when the dominant ice force frequency is closed to a natural frequency of the structure. For beams, perturbed by small nonlinearities and a small damping, the concept of quasi-modes is introduced. A quasi-mode is a linear combination of the usual eigenmodes. The large time behaviour of solutions at the instability onset is determined by a single quasi-mode, which is maximally linearly unstable.The beam model analysis leads to the conclusion that an interaction between a moving ice floe and a structure can lead to a "negative friction" for particular values of the ice floe parameters. From the analysis presented in the paper it follows that the lock-

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“…We observe here a plateau, and the results in Fig. 3 are consistent, at least qualitatively,with the results as obtained in [22,29].…”

Section: Large Time Behaviour Of the Solutions A N (τ ) Of Equation (66)supporting

confidence: 93%

“…The physical mechanism of IIV is nowadays explained by two theories: the force vibration theory, and the self-excited vibration theory. The first theory indicates that steady IIV regimes depend on the breaking frequency of the ice sheets [22,29,33].…”

Section: Introductionmentioning

confidence: 99%

A mathematical analysis of an extended model describing sea ice-induced frequency lock-in for vertically sided offshore structures

2021

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“…Early studies primarily relied on experimental methods, with the first detection of ice-induced vibration on an offshore platform occurring in 1964 [4]. Matlock et al [5] developed mathematical models based on forced vibration theory to analyze the vibration of offshore platform structures. Timco et al [6] analyzed the ice load of caisson structures in the Beaufort Sea, Canada.…”

Section: Introductionmentioning

confidence: 99%

Ice-Induced Vibration Analysis of Offshore Platform Structures Based on Cohesive Element Method

Zhang,

Wang,

Sun

et al. 2023

JMSE

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This study conducted ice-induced vibration analysis on offshore platform structures using the cohesive element method (CEM). The efficacy of this method in simulating the interaction between sea ice and the platform structure is verified by comparing it with the Hamburg Ship Modeling Pool (HSVA) ice-breaking experiment. Subsequently, the vibration response of a sea-ice-jacket platform model is investigated under both unprotected conditions and with the presence of ice-breaking cones. The findings reveal that the motion response of offshore platforms exhibits a positive correlation with the impact velocity of the ice, while the sensitivity of this impact is found to be minimal. Furthermore, the influence of different ice directions on the vibration response of offshore platforms is significant, and the shielding effect has an important impact on the platform’s response. Notably, offshore platforms equipped with 52.5-degree cones demonstrate the most effective vibration reduction, reducing the maximum acceleration by 63% compared to unprotected configurations. It is worth mentioning that as the cone angle increases, the corresponding ice-breaking cone undergoes higher load-bearing.

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“…The key of study on sea ice load acting on pier column structures is the crush process of sea ice interacting with structures. On basis of field monitoring and laboratory experiments, researchers has put forward several ice force models, such as Matlock Model [1], Maattanen Model [2], Ice Force Oscillator Model [3], Karna Model [4] and Venturella Model [5] etc. Above ice force models are the physical explains of the interaction of sea ice and structures aimed at the ice-induced vibration phenomenon, and the models has not been applied to the seismic dynamic analysis [6].…”

Section: Introductionmentioning

confidence: 99%

Analogue Simulation of Dynamic Interaction of Sea Ice and a Pier Column Structure

Song

Wu³

2012

AMM

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The process of interaction of sea ice and a pier column structure was studied by using analogue simulation method in the paper, and the dynamic ice force acting on the pier column structure was achieved. Combining with theory analysis, it modified the dynamic ice force model suggested by Croteau. The results showed that the loading stiffness suggested by Croteau is too big to use in the dynamic ice force model and the Withalm formula and simulated results are more suitable. It suggested the calculation formulas of relative displacement in ice force unloading stage and the continuous ice force in ice force continuous stage.

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Analytical Model for Ice-Structure Interaction

Cited by 28 publications

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A mathematical analysis of an extended model describing sea ice-induced frequency lock-in for vertically sided offshore structures

A mathematical analysis of an extended model describing sea ice-induced frequency lock-in for vertically sided offshore structures

Ice-Induced Vibration Analysis of Offshore Platform Structures Based on Cohesive Element Method

Analogue Simulation of Dynamic Interaction of Sea Ice and a Pier Column Structure

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