Dilated-polyhedron-based DEM analysis of the ice resistance on ship hulls in escort operations in level ice

2021 ◽  
Vol 80 ◽  
pp. 103092
Author(s):  
Lu Liu ◽  
Shunying Ji
Keyword(s):  
Ship Hulls ◽  
Dem Analysis ◽  
Level Ice ◽  
Ice Resistance

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.

scholarly journals Formulation of Ice Resistance in Level Ice Using Double-Plates Superposition

2020 ◽  
Vol 8 (11) ◽  
pp. 870
Author(s):  
Liang Li ◽  
Qingfei Gao ◽  
Alexander Bekker ◽  
Hongzhe Dai
Keyword(s):  
Elastic Plate ◽  
Approximate Model ◽  
Ice Thickness ◽  
Full Scale Test ◽  
Ship Resistance ◽  
Bending Resistance ◽  
Level Ice ◽  
Scale Test ◽  
Coulomb Criterion ◽  
Ice Resistance

The estimation of ship resistance in ice is a fundamental area of research and poses a substantial challenge for the design and safe use of ships in ice-covered waters. In order to estimate the ice resistance with greater reliability, we develop in this paper an improved Lindqvist formulation for the estimation of bending resistance in level ice based on the superposition of double-plates. In the developed method, an approximate model of an ice sheet is firstly presented by idealizing ice sheeta as the combination of a semi-infinite elastic plate and an infinite one resting on an elastic foundation. The Mohr–Coulomb criterion is then introduced to determine the ice sheet’s failure. Finally, an improved Lindqvist formulation for estimation of ice resistance is proposed. The accuracy of the developed formulation is validated using full-scale test data of the ship KV Svalbard in Norway, testing the model as well as the numerical method. The effect of ice thickness, stem angle and breadth of bow on ship resistance is further investigated by means of the developed formulation.

scholarly journals ICE PROPULSION ABILITY OF VESSELS WITH NONTRADITIONAL FORM

2020 ◽  
pp. 143-156
Author(s):  
Vasily A. Lobanov
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Empirical Equation ◽  
Main Attention ◽  
Resistance Level ◽  
Water Ice ◽  
Ship Hulls ◽  
The Impact ◽  
Ice Resistance ◽  
Different Thickness

In article the fact related to the significant increase in structure of the ice category fleet internal and mixed a river sea operation with non-traditional ship hulls forms is stated. With the CAE technologies use such vessels interaction nature with ice cakes and small ice cakes of different thickness and concentration in the ice channel is studied and analyzed. The main attention is paid to a research concerning the influence of different forms bulbous fore ends on change of the vessel ice resistance level. Qualitative features of such bulbous vessels contact with the water ice environment are noted. The statistical analysis concerning the obtained experimental data on the impact assessment related to constructive, dynamic and ice factors on ice propulsion ability of vessels with non-traditional forms is carried out. The quantitative forecast of such influence in the form of the multifactorial regression empirical equation is given.

Study on the Ship Ice Resistance Estimation Using Empirical Formulas

2014 ◽  
Author(s):  
Kyung Duk Park ◽  
Hyun Soo Kim
Keyword(s):  
Model Test ◽  
High Reliability ◽  
Main Idea ◽  
Estimation Technique ◽  
Empirical Formulas ◽  
Level Ice ◽  
Arctic Ice ◽  
Ice Model Test ◽  
Ice Resistance ◽  
Ice Model

The ice resistance estimation technique for icebreaking ships has been studied intensively over recent years to meet the need of arctic vessel design. Before testing in the ice model basin, the estimation of ship ice resistance with high reliability is very important to decide the delivered power necessary for level ice operation. The main idea of this study came from several empirical formulas by B.P. Ionov[1], E. Enkvist[2] and J.A. Shimanskii[3], in which ice resistance components such as icebreaking, buoyancy and clearing resistances were represented by the integral equations along the DLWL (Design Load Water Line). However, this study proposes modified methods considering the DLWL shape as well as the hull shape under the DLWL. In the proposed methodology, the DLWL shape for icebreaking resistance and the hull shape under the DLWL for buoyancy and clearing resistances are included in the calculation. Especially when calculating clearing resistance, the flow pattern of ice particles under the DLWL of ship is assumed to be in accordance with the ice flow observed from ice model testing. This paper also deals with application examples for a ship design and its ice model test results at the Aker arctic ice model basin. From the comparison of results from the model test and the estimation, the reliability of this estimation technique is discussed.

Theoretical Investigation on Ice Resistance Prediction Methods for Ships in Level Ice

2014 ◽  
Author(s):  
Daniela Myland ◽  
Sören Ehlers
Keyword(s):  
Physical Nature ◽  
Model Tests ◽  
Design Stage ◽  
Prediction Methods ◽  
Sufficient Information ◽  
Early Design Stage ◽  
Level Ice ◽  
Resistance Prediction ◽  
Ship Performance ◽  
Ice Resistance

The assessment of the ship performance in ice covered waters has become more and more important in view of the increased interest in Arctic field logistics and transportation. The performance of ice-going or ice breaking ships is usually defined by their ability to proceed in uniform level ice, where good performance means low ice resistance, high propulsion efficiency and continuous ice breaking. In order to assess the ice breaking performance in an early design stage, model tests may be executed or several theoretical methods may be applied to predict the ice resistance may be applied. Due to the physical nature of model tests, all processes, i.e. forces contributing to ice resistance are considered. Thus, the execution of model tests is still the most reliable method to determine the ice resistance. But with regard to the high costs of model tests there is continued demand to gain knowledge on the reliability of theoretical prediction methods. The applicability of the method of choice depends on the underlying assumptions of the method itself and thus the method’s capability to predict and consider physical phenomena of interest. In this paper model tests are used to evaluate the influence of hull shape parameters and ice conditions on the breaking process, i.e. the ice resistance and the ship performance. Based on the knowledge gained a systematic comparison of existing, representative ice resistance prediction methods is carried out. The methods considered are state-of-the-art techniques which the original publications introduced with sufficient information to allow for their use in this comparison. It focuses on the suitability of the existing methods as engineering tools for the prediction of different components, as well as the total ice resistance itself. The incorporation of the ice resistance contributions in the different prediction methods is presented and differences are identified. On this basis an assessment of the assumptions and simplifications of these different numerical methods is outlined.

Icebreaking Model Tests: Systematic Variation of Bow Lines and Main Dimensions of Hull Forms Suitable for the Great Lakes

1973 ◽  
Vol 10 (03) ◽  
pp. 236-243
Author(s):  
Bengt M. Johansson ◽  
Eero Makinen
Keyword(s):  
Great Lakes ◽  
Power Level ◽  
The Other ◽  
Systematic Variation ◽  
Bulk Carrier ◽  
Basic Form ◽  
Speed Range ◽  
Level Ice ◽  
Hull Forms ◽  
Ice Resistance

Nine bulk carrier models were tested in the Wartsila Icebreaking Model Basin (WIMB) in Helsinki, Finland. Eight of the models form a series with systematically varying parameters. This test series was the first one in which the influence of bow form, ship length and, ship beam on ice resistance was investigated systematically. The basic form was that of the existing Great Laker SS Ryerson, which was not originally designed for navigating in ice. The other models were modified in order to improve their icebreaking capability. The main objective was to study the icebreaking resistance in level ice, but in addition some tests were made for determining the ice resistance in a broken channel and for determining the steering ability of the models. All models were tested in level ice of 1, 2 and 3 ft thickness and at a speed range of 0–12 knots. Finally, a method for the calculation of the ice resistance and necessary power level of the Great Lakers is presented.

A Review of Research to Aid the Development of Commercial Arctic Marine Transportation: 1982 Trafficability Tests on the USCGC Polar Star

1985 ◽  
Vol 22 (01) ◽  
pp. 28-35
Author(s):  
Seibold Frederick
Keyword(s):  
Ice Cores ◽  
Coast Guard ◽  
The Arctic ◽  
Marine Transportation ◽  
Newport News ◽  
Research Activities ◽  
Ice Conditions ◽  
Level Ice ◽  
Ice Resistance ◽  
Resistance Tests

A multi-year "trafficability" research program was begun in 1978 to demonstrate that year-round commercial marine transportation in Arctic waters is feasible and to collect data necessary to begin developing the criteria to design and operate marine vehicles for that environment. Using U.S. Coast Guard Polar Class icebreakers, annual winter deployments had been made in 1979, 1980, and 1981 into the Bering and Chukchi Seas to collect environmental and ship performance data. Early in 1982, the fourth phase of these research activities was conducted on the USCGC Polar Star in western Alaskan waters as far north as the Arctic Circle. Participants in the research were the Maritime Administration, the U.S. Coast Guard, the State of Alaska, the Canadian Ministry of Transport, twelve participating companies of the Alaskan Oil and Gas Association, and the Newport News Shipbuilding Company. This paper reviews the results of this voyage and the data collected. The Polar Star was instrumented to continuously monitor and record propulsion and ship motion parameters and speed. Video recording equipment was used to document ice conditions. Extensive on-ice equipment was used to profile ice features and to measure other ice parameters. Numerous pressure ridges were profiled and ice cores taken to improve the understanding of Bering and Chukchi Sea winter ice conditions and ice strength. Level ice resistance tests were conducted. However, heavy level ice conditions were not encountered and it is planned to complete the level ice resistance tests in 1984. Other research tasks included an ice edge analysis, hull friction experiments, and an ice drift study.

The Resistance of Ice Breaking Ships Based on Model Tests

2015 ◽  
Author(s):  
Seong-Rak Cho ◽  
Kuk-Jin Kang ◽  
Sungsu Lee
Keyword(s):  
Model Tests ◽  
Design Stage ◽  
Preliminary Design ◽  
Factors Associated ◽  
Preliminary Design Stage ◽  
Level Ice ◽  
Resistance Prediction ◽  
Ice Resistance ◽  
Priority Factor ◽  
Ice Model

The two most important tasks of ice breaking ships are first to secure a sailing route by breaking the thick sea ice and second to sail efficiently herself for purposes of exploration and transportation in the polar seas. The resistance of ice breaking ships is a priority factor at the preliminary design stage; not only must their sailing efficiency be satisfied, but the design of the propulsion system will be directly affected. Therefore, the performance of ice-breaking ships must be accurately calculated and evaluated through the use of model tests in an ice model basin before construction starts. In this paper, a new procedure is developed, based on model tests, to estimate a ship’s ice resistance during continuous icebreaking in level ice. Some of the factors associated with crushing failures are systematically considered in order to correctly estimate her ice-breaking resistance, while the effects of the hull geometry, as reflected in the length, breadth, and draft of ships, are considered in calculating buoyancy and clearing resistance. Multiple regression analysis is calculated with each ice resistance component. This study is intended to contribute to the improvement of the techniques for ice resistance prediction with ice breaking ships.

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.

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