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.

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.

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.

Ice Resistance Calculation Methods and Their Economic Impact on Ship Design

2015 ◽  
Author(s):  
Rüdiger U. Franz von Bock und Polach ◽  
Tõnis Tõns ◽  
Sandro Erceg
Keyword(s):  
Economic Impact ◽  
Model Tests ◽  
Empirical Formulas ◽  
Panel Methods ◽  
Ice Conditions ◽  
Resistance Prediction ◽  
Semi Empirical ◽  
Ice Resistance ◽  
Ice Model ◽  
Testing Design

A ship is an investment and built to create revenue. The decision whether the design of a ship is realized or not is therefore strongly affected by the natural obstacles of mission and route. The occurrence of ice along arctic routes is such an obstacle and affects significantly the resistance and the required propulsion power. Advanced simulation environments, such as panel methods or CFD do not exist yet for ice resistance calculations and hence semi-empirical formulations or model tests need to be employed to assess or validate a design. Ice model tests impose great expenses in terms of time and money, which often does not allow testing design variations. On the other hand, the results of semi-empirical formulas might be accompanied by significant uncertainties. The academic study presented in this paper is a transit simulation on the Northern Sea Route (NSR) for the ice-capable tanker MT Varzuga (formerly MT Uikku). The study evaluates the ice conditions along several NSR alterations and the ice resistance-related performance with available semi-empirical methods and ice model tests. Finally, the economic impact of the applied ice resistance prediction methods is evaluated and the differences are quantified.

Development of a Prediction Formula for Ship Resistance in Level Ice

2014 ◽  
Author(s):  
Seong-Rak Cho ◽  
Seong-Yeop Jeong ◽  
Sungsu Lee ◽  
Kook-Jin Kang
Keyword(s):  
Extreme Environments ◽  
Prediction Equation ◽  
Regression Analyses ◽  
Prediction Formula ◽  
Resistance Components ◽  
Northern Sea Route ◽  
Level Ice ◽  
Ice Resistance ◽  
Priority Factor ◽  
Ice Model

Icebreakers are mainly classified according to the breakable thickness of level ice, although they differ slightly according to each ship’s classification and by country. The breaking performance in level ice is a priority factor for icebreakers and is directly linked to ships’ safety and survival in extreme environments. In addition, some large cargo vessels with an icebreaking capability have recently been built, and various types of commercial icebreakers will appear when the Northern Sea Route is activated in the future. In this paper, previous studies on ice resistance are reviewed and analyzed by arranging the merits and demerits of each study. We developed a new prediction equation of ice resistance by analyzing the resistance components, such as the breaking, buoyancy, and clearing resistance, and using dimensional and regression analyses on ice model tests. This procedure could be applied to large merchant vessels and is intended to contribute to the prediction of icebreakers’ ice performance.

scholarly journals Uniform deformation design of outrigger braced skyscrapers: A simplified method for the preliminary design stage

Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 395-405
Author(s):  
Arsalan Alavi ◽  
Elena Mele ◽  
Reza Rahgozar ◽  
Ehsan Noroozinejad Farsangi ◽  
Izuru Takewaki ◽  
...  
Keyword(s):  
Design Stage ◽  
Preliminary Design ◽  
Uniform Deformation ◽  
Simplified Method ◽  
Preliminary Design Stage

An Approximate Method for Intact Stability of Fishing Vessels

1999 ◽  
Vol 36 (03) ◽  
pp. 171-174
Author(s):  
Hüseyin Yilmaz ◽  
Abdi Kükner
Keyword(s):  
Design Stage ◽  
Design Parameters ◽  
Preliminary Design ◽  
Ship Stability ◽  
Fishing Vessels ◽  
Initial Stability ◽  
Intact Stability ◽  
Preliminary Design Stage ◽  
Reduce Risk ◽  
Vessel Stability

It is well known that stability is the most important safety requirement for ships. One should have some information on ship stability at the preliminary design stage in order to reduce risk. Initial stability of ships is an important criterion and can be closely evaluated in terms of form parameters and vertical center of gravity. In this study, using some sample ship data, approximate formulations are derived by means of regression analysis for the calculations expressed in terms of ship preliminary design parameters that can easily provide approximate GM calculations. Thus designers can be provided with ship stability at the preliminary design stage, and also a set of appropriate design parameters for improving vessel stability can easily be determined.

scholarly journals Fatigue life prediction in a door hinge system under uni-axial and multi-axial loading conditions

2021 ◽  
Author(s):  
Sacheen Bekah
Keyword(s):  
Axial Loading ◽  
Fatigue Analysis ◽  
Design Stage ◽  
Fe Model ◽  
Preliminary Design ◽  
Standard Requirement ◽  
Ground Vehicle ◽  
Design Engineers ◽  
Door Hinge ◽  
Preliminary Design Stage

This thesis presents the use of Finite Element (FE) based fatigue analysis to locate the critical point of crack initiation and predict life in a door hinge system that is subjected to both uni-axial and multi-axial loading. The results are experimentally validated. The FE model is further used to obtain an optimum design per the standard requirement in the ground vehicle industry. The accuracy of the results showed that FE based fatigue analysis can be successfully employed to reduce costly and time-consuming experiments in the preliminary design stage. Numerical analysis also provides the product design engineers with substantial savings, enabling the testing of fewer prototypes.

scholarly journals Fatigue life prediction in a door hinge system under uni-axial and multi-axial loading conditions

2021 ◽  
Author(s):  
Sacheen Bekah
Keyword(s):  
Axial Loading ◽  
Fatigue Analysis ◽  
Design Stage ◽  
Fe Model ◽  
Preliminary Design ◽  
Standard Requirement ◽  
Ground Vehicle ◽  
Design Engineers ◽  
Door Hinge ◽  
Preliminary Design Stage

This thesis presents the use of Finite Element (FE) based fatigue analysis to locate the critical point of crack initiation and predict life in a door hinge system that is subjected to both uni-axial and multi-axial loading. The results are experimentally validated. The FE model is further used to obtain an optimum design per the standard requirement in the ground vehicle industry. The accuracy of the results showed that FE based fatigue analysis can be successfully employed to reduce costly and time-consuming experiments in the preliminary design stage. Numerical analysis also provides the product design engineers with substantial savings, enabling the testing of fewer prototypes.

scholarly journals An Approximate Method for Calculation of Mean Statistical Value of Ship Service Speed on a Given Shipping Line , Useful in Preliminary Design Stage

2015 ◽  
Vol 22 (1) ◽  
pp. 28-35
Author(s):  
Katarzyna Żelazny
Keyword(s):  
Wind Waves ◽  
Parametric Method ◽  
Weather Conditions ◽  
Economic Effects ◽  
Design Stage ◽  
Design Parameters ◽  
Preliminary Design ◽  
Screw Propeller ◽  
Calm Water ◽  
Preliminary Design Stage

Abstract During ship design, its service speed is one of the crucial parameters which decide on future economic effects. As sufficiently exact calculation methods applicable to preliminary design stage are lacking the so called contract speed which a ship reaches in calm water is usually applied. In the paper [11] a parametric method for calculation of total ship resistance in actual weather conditions (wind, waves, sea current), was presented. This paper presents a parametric model of ship propulsion system (screw propeller - propulsion engine) as well as a calculation method, based on both models, of mean statistical value of ship service speed in seasonal weather conditions occurring on shipping lines. The method makes use of only basic design parameters and may be applied in preliminary design stage.

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