Transient responses of a VLFS during landing and take-off of an airplane

Kashiwagi, Masashi

doi:10.1007/s00773-003-0168-0

Cited by 103 publications

(52 citation statements)

References 3 publications

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“…The problem was investigated within the linear theory of hydroelasticity (see [1] [2] [3] [4] [5]) and 5 fully nonlinear model (see [6] [7] [8] [9] [10]). Transient problems of moving loads with application to the aircraft landing on ice, in particular, were studied in [11] [12] [13] [14] [15]. The problem of loads moving Depending on environmental conditions and place on a river or offshore, where the ice have to be broken and removed, the "resonant method of icebreaking" is supplemented with some other techniques to increase the stresses in the ice.…”

Section: Introductionmentioning

confidence: 99%

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The response of ice cover to a load moving along a frozen channel

Shishmarev

Хабахпашева

Korobkin

2016

Applied Ocean Research

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Deflections and stresses in an ice cover of a frozen channel caused by a load moving with a constant speed along the channel are studied. The channel is of rectangular cross section. The ice cover is isotropic and clamped to the walls of the channel. The fluid in the channel is inviscid and incompressible. The external load is modeled by a localized smooth pressure distribution moving along the central line of the channel. The ice cover is modeled as a viscoelastic plate. Deflection of the ice and strains in the ice plate are independent of time in the coordinate system moving together with the load. The effect of the channel walls on the ice response is studied. This effect can be significant in experiments with loads moving in ice tanks. The linear hydroelastic problem is solved by using the Fourier transform along the channel and the method of normal modes across the channel. It is found that the presence of the vertical walls of the channel reduces the ice deflection but increases the elastic strains in the ice plate. The effects of the load speed, width and depth of the channel on the hydroelastic response of the ice cover are studied in detail. In contrast to the problem of a load moving on ice sheets of infinite extent, there are infinitely many critical speeds of hydroelastic waves in a frozen channel. Correspondingly, there are many values of the speeds of a moving load at which the stresses in the ice cover are amplified. The obtained deflections and strains in the canned ice cover are compared with the corresponding solutions for the infinite ice plate and with the solutions of simplified problems without account for the dynamic component of the liquid pressure. It is shown that the models of ice response without hydrodynamic component of the pressure provide correct stresses in the ice sheet only for very low speeds of the moving load.

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Section: Introductionmentioning

confidence: 99%

“…The corresponding solution w ∞ (x, y) for the infinite ice plate and the same external load (2) is obtained by applying the Fourier transform in y to equation (12). Then…”

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confidence: 99%

The response of ice cover to a load moving along a frozen channel

Shishmarev

Хабахпашева

Korobkin

2016

Applied Ocean Research

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“…This makes the coefficients in the load models frequency independent such that they can be used in a straightforward manner in time domain. It can however be challenging to model the self-excited forces accurately using these simplified approaches, which has resulted in a number of suggestions for improvements, for instance, using convolution integrals or indicial functions [3][4][5][6] to simulate the fluid memory effect. To guarantee both computational accuracy and efficiency, state space models [7][8][9][10][11][12] are also commonly used in the modelling of the hydrodynamic and aerodynamic selfexcited forces.…”

Section: Introductionmentioning

confidence: 99%

Time Domain Modelling of Frequency Dependent Wind and Wave Forces on a Three-Span Suspension Bridge With Two Floating Pylons Using State Space Models

Yang

Øiseth

Moan

2017

Volume 9: Offshore Geotechnics; Torgeir Moan Honoring Symposium

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Floating suspension bridges, one of several new designs to make it possible to cross deep and wide fjords, consist of three spans and supported by two tension leg platforms and two fixed traditional concrete pylons. Geometric nonlinearities, nonlinear aerodynamic and hydrodynamic forces and nonlinear mooring systems can become of high importance. Time domain methods are commonly applied when nonlinearities need to be considered. The main challenge in time domain simulation of the floating suspension bridge is the modelling of frequencydependent aerodynamic self-excited forces and hydrodynamic radiation forces. This paper shows how rational functions fitted to aerodynamic derivatives and hydrodynamic added mass and potential damping can be converted to state space models to transform the frequency-dependent forces to time-domain. A user element is implemented in the software ABAQUS to be able to include the self-excited forces in the dynamic analysis. The element is developed as a one node element that is included in the nodes along the girder and the tension leg platforms. The responses of the floating suspension bridge under turbulent wind forces and first-order wave excitation forces are calculated in a comprehensive case study and compared with results obtained using a multi-mode frequency domain approach to illustrate the performance of the presented time-domain methodology.

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“…The presented procedure can be used for the hydroelastic analysis of very large floating structures (VLFS), which behave as a sheet in the sea waves, [24]. An analytical formulation of the assumed modes simplifies the determination of hydrodynamic coefficients, i.e.…”

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confidence: 99%

An Analytical Solution to Free Rectangular Plate Natural Vibrations by Beam Modes – Ordinary and Missing Plate Modes

et al. 2016

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SummaryRelatively simple analytical procedures for the estimation of natural frequencies of free thin rectangular plates, based on the Rayleigh quotient and the Rayleigh-Ritz method, are presented. First, natural modes are assumed in the usual form as products of beam natural modes in the longitudinal and transverse directions, satisfying the grillage boundary conditions. Based on a detailed FEM analysis, the missing of some natural modes, defined as a sum and a difference of the cross products of beam modes, is noted. The frequencies of these modes are very similar and identical in some special cases, manifesting in such a way a double frequency phenomenon. These families of natural mode shapes form a complete natural frequency spectrum of a free rectangular plate as a novelty. The reliable approximation of natural modes enables the application of the Rayleigh quotient for the estimation of higher natural frequencies. The application of the developed procedure is illustrated by the case of a free thin square plate. The obtained results are compared with those determined by FEM and also with rigorous ones from the relevant literature based on the Rayleigh-Ritz method. The achieved accuracy is acceptable from the engineering point of view. Furthermore, the same problem is solved by the Rayleigh-Ritz method using approximate natural modes as mathematical ones. Direct and iterative procedures are presented. A small number of mathematical modes and iteration steps are sufficient to achieve reliable results.

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Transient responses of a VLFS during landing and take-off of an airplane

Cited by 103 publications

References 3 publications

The response of ice cover to a load moving along a frozen channel

The response of ice cover to a load moving along a frozen channel

Time Domain Modelling of Frequency Dependent Wind and Wave Forces on a Three-Span Suspension Bridge With Two Floating Pylons Using State Space Models

An Analytical Solution to Free Rectangular Plate Natural Vibrations by Beam Modes – Ordinary and Missing Plate Modes

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