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.

A Comparison of Ice Loads From Level Ice and Ice Ridges on Sloping Offshore Structures Calculated in Accordance With Different International and National Standards

2006 ◽  
Author(s):  
Per Kristian Bruun ◽  
Ove Tobias Gudmestad
Keyword(s):  
Barents Sea ◽  
Slope Angle ◽  
Offshore Structures ◽  
Interaction Process ◽  
International Standards ◽  
Structure Interaction ◽  
Ice Load ◽  
Ice Loads ◽  
Level Ice

Existing national and international standards for determination of level ice and ice ridge loads on sloping offshore structures recommend different methods for the analysis. The objective of this paper is to review the codes and standards recommendations regarding ice-sloping structures interaction process and highlight the differences between them. Development of offshore hydrocarbon fields in the Eastern Barents Sea is foreseen to take place in the near future while developments already take place in the Pechora Sea and offshore Sakhalin as well as in the Northern Caspian Sea. One of the most difficult issues facing the designer of offshore structures for these areas is how to design for loads from level ice and ice ridges. The ice load considerations will have a major effect on the form and cost of these structures. It is known that different designers use very different ice load estimates (Shkhinek et al., 1994). The standards recommend different methods for determination of the global ice loads on both cone-shaped and sloping rectangular structures. For determination of the global ice loads on these types of structures, it is obvious that the ice-structure interaction process must be identified. Rubble effects must be included in the analysis. The ice-structure interaction process for these geometries depends on many factors, such as; the ice thickness, ice strength, ice-structure friction coefficient, ice velocity, width of the structure and slope angle of the structure. The methods for determination of ice loads recommended by the different standards are very much influenced by local ice conditions and the parameters listed above are given different importance in the different standards. The differences in loads calculated by using the different standards and their validity for the ice-structure interaction process have been investigated and example calculations are presented to show these differences. It is thought that the paper may be of interest for those preparing the new ISO standard (ISO 19906) on Arctic Offshore Structures.

scholarly journals Numerical Simulation of a Polar Ship Moving in Level Ice Based on a One-Way Coupling Method

2020 ◽  
Vol 8 (9) ◽  
pp. 692
Author(s):  
Bao-Yu Ni ◽  
Zi-Wang Chen ◽  
Kai Zhong ◽  
Xin-Ang Li ◽  
Yan-Zhuo Xue
Keyword(s):  
Numerical Simulation ◽  
Failure Process ◽  
Coupling Method ◽  
Crack Propagation Process ◽  
Order Of Magnitude ◽  
Level Ice ◽  
Ice Failure ◽  
Ice Resistance ◽  
Ship Speed ◽  
Good Agreement

In most previous ice–ship interaction studies involving fluid effects, ice was taken as unbreakable. Building breakable level ice on water domain is still a big challenge in numerical simulation. This paper overcomes this difficulty and presents a numerical modeling of a ship moving in level ice on the water by using a one-way CFD-DEM (computational fluid dynamics-discrete element method) coupling method. The detailed numerical processes and techniques are introduced. The ice crack propagation process including radial and circular cracks have been observed. Numerical results are compared with previous experimental data and good agreement has been achieved. The results show that water resistance is an order of magnitude smaller than ice resistance during the ice-breaking process. Ice resistance shows strong oscillation along with ice failure process, which are affected by ship speed and ice thickness significantly.

Experimental Investigation of Aspects Influencing the Level Ice Resistance of Ships With Non-Typical Icebreaking Bow Shapes

2021 ◽  
Author(s):  
Daniela Myland ◽  
Quentin Hisette ◽  
Emre Cilkaya ◽  
Yusuf Sefa Özhan
Keyword(s):  
Ice Sheets ◽  
Relevant Information ◽  
Interaction Process ◽  
Total Resistance ◽  
Ship Model ◽  
Load Cells ◽  
Level Ice ◽  
Ice Resistance ◽  
Different Thickness ◽  
Ice Model

Abstract For non-typical icebreaking ships the hull-ice interaction process in level ice comprises a combination of many different phenomena which is difficult to be described by existing straightforward approaches. In order to gain knowledge about the operability of such non-typical hull shapes in level ice, a study has been carried out to identify and evaluate the level ice resistance as well as its distribution along the hull of ships with non-typical icebreaking bow shapes with high stem and/or small waterline angles. For this purpose, one ship model has been manufactured and instrumented with several multi-axis load cells in the bow region of the waterline as well as with one large six-component load scale between the bow and the stern. Performing resistance model tests at several loading conditions in model ice sheets of different thickness and at multiple speed values allows obtaining relevant information to meet the goals of the study. The developed methodology and the analysis of the measured loads have been described in previous publications. As direct continuation, the present paper focuses on investigation of the ice floe characteristics and its linkage to the ice properties. Moreover, analysis results related to the crushing portion of the total resistance in ice, the friction between ice and ship model hull as well as the ship model motions during ice model testing are presented within the paper.

Methodology to Investigate the Icebreaking Process of Ships With Non-Typical Icebreaking Bow Shapes

2020 ◽  
Author(s):  
Quentin Hisette ◽  
Daniela Myland
Keyword(s):  
Ice Sheets ◽  
Relevant Information ◽  
Model Tests ◽  
Interaction Process ◽  
Analysis Procedure ◽  
Load Cells ◽  
Level Ice ◽  
Ice Resistance ◽  
Different Thickness ◽  
Ice Model

Abstract For non-typical icebreaking ships the hull-ice interaction process in level ice comprises a combination of many different phenomena which is difficult to be described by existing straightforward approaches. In order to gain knowledge about the level ice resistance of such non-typical hull shapes for operation in ice, a methodology is developed and presented to identify and evaluate the level ice resistance as well as its distribution along the hull of ships with non-typical icebreaking bow shapes with high stem and/or small waterline angles. For this purpose, one ship model has been manufactured and instrumented with several multi-component load cells in the bow region of the waterline as well as with one large six-component load scale between the bow and the stern. Performing resistance model tests at several loading conditions, in model ice sheets of different thickness and at multiple speed values allows obtaining relevant information to meet the goals of the study. The paper focuses on the methodology used for the ice model tests and its analysis. Instrumentation of the model is fully described, together with an overview of the testing matrix and model test observations. Analysis procedure is described in details and applied on a representative test run of the campaign.

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.

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.

scholarly journals Calculation Methods of Icebreaking Capability for a Double-Acting Polar Ship

2020 ◽  
Vol 8 (3) ◽  
pp. 179 ◽  
Author(s):  
Li Zhou ◽  
Feng Diao ◽  
Ming Song ◽  
Yue Han ◽  
Shifeng Ding
Keyword(s):  
Model Test ◽  
Dynamic Method ◽  
Model Tests ◽  
State Research ◽  
Dynamic Methods ◽  
Level Ice ◽  
Ice Resistance ◽  
Test Result ◽  
Good Agreement ◽  
Key Parameter

As a key parameter, icebreaking capability is often used to judge whether a polar ship could navigate in level ice at a certain speed. This paper presents two methods to calculate icebreaking capability. The first one is a static method based on the estimation of ice resistance under different ice thicknesses and ship speeds. The second is a dynamic method that involves solving the equation of motion. A series of model tests with a double-acting icebreaking tanker were also carried out in the ice basin of the Krylov State Research Center to measure ice resistances. The simulated ice resistances were compared with model tests results for both ahead and astern running operations. The calculated icebreaking capability based on static and dynamic methods was validated with the model test result. A good agreement was achieved between measurement and simulation. The discrepancy between the model test result and the result simulated by the static or dynamic method was minor.

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

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