scholarly journals Model-scale tests on ice-structure interaction in shallow water, Part I: Global ice loads and the ice loading process

2022 ◽  
Vol 81 ◽  
pp. 103106
Author(s):  
Ida Lemström ◽  
Arttu Polojärvi ◽  
Jukka Tuhkuri
Keyword(s):  
Shallow Water ◽  
Structure Interaction ◽  
Loading Process ◽  
Model Scale ◽  
Ice Loads

Parameter Sensitivity in Numerical Modelling of Ice-Structure Interaction With Cohesive Element Method

2016 ◽  
Author(s):  
Dianshi Feng ◽  
Sze Dai Pang ◽  
Jin Zhang
Keyword(s):  
Element Model ◽  
Offshore Structures ◽  
Parameter Sensitivity ◽  
The Arctic ◽  
Cohesive Element ◽  
Structure Interaction ◽  
Marine Structure ◽  
Ice Loads ◽  
The Stability ◽  
Element Method

The increasing marine activities in the Arctic has resulted in a growing demand for reliable structural designs in this region. Ice loads are a major concern to the designer of a marine structure in the arctic, and are often the principal factor that governs the structural design [Palmer and Croasdale, 2013]. With the rapid advancement in computational power, numerical method is becoming a useful tool for design of offshore structures subjected to ice actions. Cohesive element method (CEM), a method which has been widely utilized to simulate fracture in various materials ranging from metals to ceramics and composites as well as bi-material systems, has been recently applied to predict ice-structure interactions. Although it shows promising future for further applications, there are also some challenging issues like high mesh dependency, large variation in cohesive properties etc., yet to be resolved. In this study, a 3D finite element model with the use of CEM was developed in LS-DYNA for simulating ice-structure interaction. The stability of the model was investigated and a parameter sensitivity analysis was carried out for a better understanding of how each material parameter affects the simulation results.

The Design of an Eight-Oared Rowing Shell

1993 ◽  
Vol 30 (02) ◽  
pp. 84-99
Author(s):  
Carl A. Scragg ◽  
Bruce D. Nelson
Keyword(s):  
Shallow Water ◽  
High Speed ◽  
Hull Form ◽  
Model Scale ◽  
Minimum Drag ◽  
Final Design ◽  
Minimum Displacement ◽  
Resistance Curves ◽  
Hull Forms ◽  
Minimum Resistance

Rules governing the design of rowing shells do not restrict basic hull parameters. In designing a new eight-oared rowing shell for international ard Olympic competition, the authors sought a high speed, minimum drag hull form, subject only to the constraints on minimum displacement and roll stability. An investigation of optimum hull parameters using analytically determined resistance curves was made. Optimum hull parameters for both deep and shallow water racing are presented. Using the hull parameters determined for minimum resistance at racing speeds in shallow water, several new hull forms were created and analyzed in both deep and shallow water. Two promising final design candidates were proposed for model-scale testing. Results of both steady and unsteady towing tests are presented.

Numerical Simulations of Continuous Icebreaking Process With Different Heel Angles in Level Ice

2018 ◽  
Author(s):  
Feng Wang ◽  
Zao-Jian Zou ◽  
Hai-Peng Guo ◽  
Yi-Zhou Ren
Keyword(s):  
Measured Data ◽  
Interaction Process ◽  
Marine Structures ◽  
Structure Interaction ◽  
Ice Loads ◽  
Level Ice ◽  
Breaking Length ◽  
Increasing Trends ◽  
Ice Resistance ◽  
Good Agreement

Based on cohesive element method (CEM), the continuous icebreaking process with different heel angles in level ice are simulated in this paper. The simulations are established in FEM software LS-DYNA and an icebreaking tanker - MT Uikku is assumed advancing with the certain heel angle in level ice. Firstly, the comparisons are made between the simulations and the model tests for the cases with zero heel angle. A good agreement is obtained between the simulated and measured data. Then the effects of different heel angles on ice resistance and ice breaking patterns are investigated and analyzed. The results show that ice resistance, average ice breaking length and average broken channel width present increasing trends with the increase of ship heel angle. The applied methods show a wide prospect to predict ice loads on marine structures in the level ice and simulate the ice-structure interaction process.

Results of Field Monitoring on Ice Actions on Conical Structures

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Ning Xu ◽  
Qianjin Yue ◽  
Yan Qu ◽  
Xiangjun Bi ◽  
Andrew Palmer
Keyword(s):  
Bohai Sea ◽  
Field Work ◽  
Interaction Process ◽  
Structure Interaction ◽  
Interaction Processes ◽  
Ice Conditions ◽  
Conical Structure ◽  
Ice Loads ◽  
Ice Forces ◽  
Conical Structures

Ice-structure interaction plays a central part in determining ice loads and ice-induced vibrations. This is a controversial research issue, and many factors make the problem more complicated. The authors have been monitoring several ice resistant structures in the Bohai Sea for 20 years and have measured ice forces and simultaneously observed ice-structure interaction processes. This paper describes typical physical ice sheet–conical structure interaction processes, field data, and theoretical explanations for different ice conditions and structure dimensions. The conclusions are more widely applicable, and we relate them to field work on ice resistant conical structures in other ice-covered regions. Further work will quantify ice loads on conical structures once the interaction process is understood.

Velocity Effects on Wide Sloping Structure Ice Loads

2016 ◽  
Author(s):  
Yihe Wang ◽  
Leong Hien Poh
Keyword(s):  
Boundary Conditions ◽  
Potential Theory ◽  
Sea Water ◽  
Ice Sheet ◽  
Dynamic Effect ◽  
Added Mass ◽  
Hydrodynamic Effect ◽  
Governing Equations ◽  
Structure Interaction ◽  
Ice Loads

Sloping structures are widely used in ice-infested waters because of their ability to reduce the ice loads by changing the ice sheet failure mode from crushing to bending. Model test data showed significant velocity effects on breaking component of sloping structure ice loads (Matskevitch, 2002), which are induced by both the dynamic effect of the ice sheet and the hydrodynamic effect of the sea water beneath the ice sheet. However, existing design codes and most models idealize the underlying sea water as a Winkler-type elastic foundation, without taking into account the velocity effects in the calculation of ice loading. The added mass concept has been utilized by researchers to incorporate the hydrodynamic effect (Sørensen, 1978; Sodhi, 1987), though the potential theory was reported to be more adequate in capturing the (additional) forces from the fluid foundation because the added mass varies with time and space (Zhao and Dempsey, 1996; Lubbad et al, 2008). In general, however, there is limited work done on the incorporation of velocity effects into the computation of ice breaking loads on sloping structures. In this paper, we study the velocity effects on ice breaking load through a two-dimensional problem. The ice-structure interaction problem is studied numerically by incorporating the dynamic effect of the ice sheet and the hydrodynamic effect of the sea water beneath the ice sheet. The ice-fluid interaction is captured by adopting the Euler-Bernoulli beam theory for the ice sheet and the potential theory for the fluid foundation, leading to a set of two governing equations with two loading boundary conditions. For ease of computation, we consider sub-problems with the same set of governing equations, each with modified loading boundary conditions. The numerical models are first validated against available analytical solutions for a simple problem before solving for the sub-problems. Finally, the solution to the original set of governing equations defining the ice-structure interaction is obtained from the superposition of the solutions to two sub-problems. Initial results show that the velocity effects can have a significant influence on ice breaking loads for wide sloping structures.

scholarly journals A review of discrete element simulation of ice–structure interaction

2018 ◽  
Vol 376 (2129) ◽  
pp. 20170335 ◽  
Author(s):  
Jukka Tuhkuri ◽  
Arttu Polojärvi
Keyword(s):  
Sea Ice ◽  
Failure Process ◽  
Discrete Element ◽  
Offshore Structures ◽  
Lessons Learned ◽  
Structure Interaction ◽  
Large Numbers ◽  
Ice Loads ◽  
Discontinuous Medium ◽  
Ice Failure

Sea ice loads on marine structures are caused by the failure process of ice against the structure. The failure process is affected by both the structure and the ice, thus is called ice–structure interaction. Many ice failure processes, including ice failure against inclined or vertical offshore structures, are composed of large numbers of discrete failure events which lead to the formation of piles of ice blocks. Such failure processes have been successfully studied by using the discrete element method (DEM). In addition, ice appears in nature often as discrete floes; either as single floes, ice floe fields or as parts of ridges. DEM has also been successfully applied to study the formation and deformation of these ice features, and the interactions of ships and structures with them. This paper gives a review of the use of DEM in studying ice–structure interaction, with emphasis on the lessons learned about the behaviour of sea ice as a discontinuous medium. This article is part of the theme issue ‘Modelling of sea-ice phenomena’.

Main Factors of Ice Sheet-Conical Structure Interaction Process Based on Field Monitoring

2009 ◽  
Author(s):  
Ning Xu ◽  
Yan Qu ◽  
Qianjin Yue ◽  
Xiangjun Bi ◽  
Andrew Clennel Palmer
Keyword(s):  
Ice Sheet ◽  
Field Work ◽  
Interaction Process ◽  
Structure Interaction ◽  
Interaction Processes ◽  
Ice Conditions ◽  
Conical Structure ◽  
Ice Loads ◽  
Ice Forces ◽  
Conical Structures

Ice-structure interaction plays a central part in determining ice loads and ice-induced vibrations. This is a controversial research issue, and many factors make the problem more complicated. The authors have been monitoring several ice resistant structures in the Bohai Sea for twenty years, and have measured ice forces and simultaneously observed ice-structure interaction processes. This paper describes typical physical ice sheet-conical structure interaction processes, field data and theoretical explanations, for different ice conditions and structure dimensions. The conclusions are more widely applicable, and we relate them to field work on ice-resistant conical structures in other ice-covered regions. Further work will quantify ice loads on conical structures once the interaction process is understood.

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