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Wyszukujesz frazę "floating" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Loads Exerted on a Cylindrical Structure by Floating Ice Modelled as a Viscous-Plastic Material
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241476.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
floating ice
cylindrical structure
rheology
viscosity
plasticity
Opis:
In this paper the problem of interaction between a coherent floating ice field and a fixed, rigid, vertically-walled circular cylinder is investigated. The ice cover, of horizontal dimensions significantly larger than the characteristic size of the structure, is assumed to be driven against the cylinder by wind drag forces. The ice is treated as a viscous-plastic material, in which the permissible stress states in the horizontal plane are bound by an elliptic yield curve. By using an associated flow rule, a constitutive law, involving two parameters defining the ice strength in compression and much smaller strength in extension, is derived in order to describe the behaviour of the material. The law predicts distinct responses during yield (occurring at high strain-rates) and during the flow when the yield condition does not apply (at lower strain-rates). The results of numerical calculations performed by a finite difference method illustrate, for chosen ice rheological parameters, the distribution of contact stresses at the ice - structure interface. Two forms of boundary conditions at the cylinder wall, free-slip and no-slip, are considered, and their effects on the horizontal loads sustained by the structure are examined. In addition, the results for the viscous-plastic rheology of ice are compared with those obtained on the assumption of a purely viscous behaviour of ice.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 2; 105-126
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Loads on an Off-Shore Structure due to an Ice Floe Impact
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241420.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
floating ice
offshore structure
dynamic impact
brittle fracture
Opis:
In the paper, the problem of dynamic impact of a floating ice sheet at an off-shore structure is considered. It is assumed that during an interaction event the dominant mechanism is the brittle fracture of ice at the ice--structure interface, that is, elastic and creep effects in ice are ignored. Since in natural conditions the edge of floating ice is usually irregular, the contact between a floe and an engineering object is imperfect. Thus, at any one time, the failure of ice occurs only in a number of small zones along a structure wall, leading to a highly irregular variation of forces exerted on the structure during the impact process. It is supposed in the analysis that the successive small-scale fracture events at the contact surface occur at random, and all these small-scale events take place independently of each other. An off-shore structure is modelled as a fixed and rigid circular cylinder with vertical walls. For an adopted geometry of the ice sheet, its initial horizontal velocity, and the variety of parameters describing the limit failure stresses in ice, the history of total loads sustained by the structure and the floe velocity variation are illustrated for a typical impact event. Furthermore, probability distributions for maximum impact forces exerted on the structure, depending on the floe size, its thickness and initial velocity, are determined.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2007, 54, 2; 77-94
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Loads exerted by floating ice on a cylindrical structure
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241206.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
floating ice
plate
rheology
creep buckling
finite difference method
Opis:
The paper is concerned with the problem of interaction between a coherent floating ice cover and a fixed, rigid, vertically-walled circular cylinder. The ice cover, of horizontal dimensions considerably larger than the size of the structure, is assumed to be driven against the structure by wind and water current drag stresses. The floating ice cover is modelled as a plate that is subject to the action of horizontal forces and transverse bending due to the reaction of underlying water. During an interaction event, of a quasi-static character, the ice is modelled as a creeping material the behaviour of which is described by a viscous flow law with two, bulk and shear, viscosities. The viscosities change dramatically in their magnitudes during a transition from converging to diverging deformation of the material to reflect the fact that floating ice offers much less resistance to tensile rather than compressive stresses. By numerical simulations carried out by a finite difference method, the influence of the ice rheological parameters on the distribution of contact stresses at the ice - structure interface is investigated. Two types of boundary conditions at the interface, free-slip and no-slip, are considered, and their effects on the loads sustained by the structure are compared. In addition, creep buckling of the ice sheet near the structure is analysed to determine the critical time at which ice starts to fail due to exceeding its flexural strength at given loading conditions.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 1; 39-58
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element simulations of floating ice - engineering structure interactions
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/240982.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
finite element simulations
floating ice cover
rigid engineering structure
Opis:
In this paper the problem of interaction between a coherent floating ice cover and a rigid engineering structure is considered. It is assumed that the ice cover, of horizontal dimensions considerably larger than the dimensions of the structure, is driven by wind and water current drag forces. During the interaction process of a quasi-static character, ice is assumed to behave as a creeping material, with a rheology described by the viscous fluid flow law. The ice cover is treated as a plate which sustains both bending due to the vertical reaction of the underlying water and the action of horizontal forces, which gives rise to the development of creep buckles in the plate and subsequently leads to the flexural failure of ice. An approximate solution to the problem is constructed by employing the finite element method. The results of numerical simulations illustrate the magnitudes of the forces exerted on the structure and their dependence on the wind direction and the structure geometry. In addition, the ice plate deflection in the vicinity of the structure is illustrated, and the values of the critical time at which the plate starts to fail by creep buckling are determined to show their dependence on the ice thickness, temperature, and type.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 3; 251-268
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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