• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.469-475
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• 2010

The operation scenarios, types of ice, draft and propulsion system are important design point on the beginning stage of the ice breaking vessel. The concept of hull form in ice breaking vessel has to compromise the performance according to the operation route especially if ship is operating in ice and ice free water. The several hull forms were proposed to optimize the capability of the vessel in this paper. The effect of hull form according to type of ice is also discussing and explaining the ice resistance in each ice type as like pack ice, brash ice, level ice, rubble ice and ice ridge. The draft effect was examined and propulsion system for example FPP(Fixed pitch propeller), CPP(Controllable pitch propeller) and POD system was compared focusing on the propulsion efficiency.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.183-183
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• 2012

As as result of development of new voyage route, especially Baltic seas, it is necessary for the design to meet ice class requirements as vessels continue to increase in this route. For this reason Finish-Swedish ice class has recently amended a regulation on the propulsion shafting design and engine output required for the ships which will be navigable in the brash ice channels broken by ice-breakers in Baltic seas. Therefore, this study shows the appropriate calculation methods for the design of engine output and propulsion shafting system based on ice class requirements.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.667-674
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• 2014

A ship's propulsion shafting system is subjected to varying magnitudes of intermittent loadings that pose great risks such as failure. Consequently, the dynamic characteristic of a propulsion shafting system must be designed to withstand the resonance that occurs during operation. This resonance results from hydrodynamic interaction between the propeller and fluid. For ice-class vessels, this interaction takes place between the propeller and ice. Producing load- and resonance-induced stresses, the propeller-ice interaction is the primary source of excitation, making it a major focus in the design requirements of propulsion shafting systems. This paper examines the transient torsional vibration response of the propulsion shafting system of an ice-class research vessel. The propulsion train is composed of an electric motor, flexible coupling, spherical gears, and a propeller configuration. In this paper, the theoretical analysis of transient torsional vibration and propeller-ice interaction loading is first discussed, followed by an explanation of the actual transient torsional vibration measurements. Measurement data for the analysis were compared with an applied estimation factor for the propulsion shafting design torque limit, and they were evaluated using an existing international standard. Addressing the transient torsional vibration of a propulsion shafting system with an electric motor, this paper also illustrates the influence of flexible coupling stiffness design on resulting resonance. Lastly, the paper concludes with a proposal to further study the existence of negative torque on a gear train and its overall effect on propulsion shafting systems.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.321-328
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• 2015

In recent years, there has been an increasing demand to apply the new IACS(International Association of Classification Societies) standards for ice and polar-classed ships. For ice-class vessel propulsion system, the ice impact torque design criterion is defined as a periodic harmonic function in relation to the number of the propeller blades. However, irregular or transient ice impact torque is assumed to occur likely in actual circumstances rather than these periodic loadings. In this paper, the reliability and torsional vibration characteristics of a comparatively large six-cylinder marine diesel engine for propulsion shafting system was examined and reviewed in accordance with current regulations. In this particular, the transient ice impact torque and excessive vibratory torque originating from diesel engine were interpreted and the resonant points identified through theoretical analysis. Several floating ice impacts were carried out to evaluate torque responses using the calculation method of classification rule requirement. The Newmark method was used for the transient response analysis of the whole system.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.4
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• pp.708-719
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• 2015

The two most important tasks of icebreakers 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 icebreakers 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 icebreakers must be accurately calculated and evaluated through the use of model tests in an ice tank before construction starts. In this paper, a new procedure is developed, based on model tests, to estimate a ship's ice breaking resistance during continuous ice-breaking in ice. Some of the factors associated with crushing failures are systematically considered in order to correctly estimate her ice-breaking resistance. This study is intended to contribute to the improvement of the techniques for ice resistance prediction with ice breaking ships.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.463-468
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• 2011

The prospect of Arctic trade transportation opening on a year-round basis creates a vast opportunity of exploring untapped resources and shortened navigational routes. However, the environment's remoteness and lack of technical experiences remains a big challenge for the maritime industry. With this, engine designers and makers are continually investigating, specifically optimizing propulsion shafting system design, to meet the environmental and technical challenges of the region. Further, classification societies recognize the need to upgrade the Unified Rules concerning elements to meet current Polar requirements. Hence in this paper, excitation torque calculation on Polar class vessels propulsion shafting system will be reviewed. The propeller - ice interaction load effect, which is a main consideration of excitation source of Polar Class propulsion shafting system, on shaft design calculation will be analyzed.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.95-103
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• 2024

The propulsion technology used in unmanned Aerial Vehicles (UAVs)—which represent one of the most important development directions in aviation—is significantly related to their flight performance. This review paper discusses the different types of propulsion technologies used in unmanned aerial vehicles, namely the internal combustion engine (reciprocating, rotary, and gas turbine engines), the hybrid system, and the pure electric system. In particular, this paper presents and discusses the classification, working principles, characteristics, and critical technologies of these types of propulsion systems. These findings are expected to be helpful in establishing a development framework, comprehensive views, and multiple comparisons of future UAV propulsion systems.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.6
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• pp.20-29
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• 2003

When Arctic offshore development in the 1970's first led to the consideration of ice capable tankers, there was a high level of uncertainty over design requirements for both safety and ship performance. Also here was a lack of reliable methods to evaluate design proposals. Since that time, improved understanding of the ice environment has raised the confidence of design specifications. Parallel developments have resulted in a suite of engineering tools for ship performance evaluation at the design stage Recent development of offshore and near shore oil and gas reserves in several countries together with economic studies of increased transportation through the Russian Arctic has newly introduced the interest in ice capable tanker design. in response, Samsung Heavy Industries (SHI) applied its experience in tanker design and construction to the design of a specialized tanker with ice capability. SHI produced two prototype hull designs for further study. The performance of both hulls and of the propellers was evaluated at the Institute for Marine Dynamics (IMD) in St. John's, Newfoundland This paper discusses the development of the design, describes the model experiments to determine performance and variations, and presents the results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1166-1176
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• 2011

The prospect in opening the arctic trade transportation route on a year-round basis offers vast opportunity of exploring untapped resources and shortened navigational routes. In addition, the environment's remoteness and lack of technical experiences remains a big challenge for the maritime industry. With this, engine designers and makers are continually investigating, specifically optimizing propulsion shafting system design, to meet the environmental and technical challenges of the region. The International Association of Classification Society, specifically machinery requirements for polar class ships(IACS UR13), embodies the propulsion shafting design requirements for ice class vessels. However, the necessity to upgrade the various features of the unified rules in meeting current polar requirements is acknowledged by IACS and other classification societies. For the polar class propulsion shafting system, it is perceived that the main source of excitation will be the propeller - ice load interaction. The milling - and the impact load, in addition to the load cases interpreted by IACS, contribute greatly to the overall characteristic of the system and due considerations are given during the propulsion design stage. This paper will expound on the excitation load estimation factors affecting the dynamic response of the different propulsion shafting system design. It is anticipated that detailed understanding of these factors will have a significant role during propulsion shafting design in the future.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.3
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• pp.208-215
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• 2011

A full-scale field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. The first Korean icebreaking research vessel 'ARAON', after her delivery in late 2009, had a sea ice field trial in the Arctic Sea during July-August, 2010. This paper describes the test procedures and data analysis on the icebreaking performance of the IBRV ARAON. The data gathered from the icebreaking performance test in the Chukchi Sea and the Beaufort Sea during the Arctic voyage of ARAON includes the speed and engine power of the ship as well as sea ice thickness and strength data. The air temperature, wind speed and heading of the ship were also measured during each sea ice trial. The ARAON was designed to break 1 m thick level ice with a flexural strength of 630kPa at a continuous speed of 3knots. She is registered as a KR POLAR 10 class ship. The principal dimensions of ARAON are 110 m, 19 m and 6.8 m in length, breadth and draft respectively. She is equipped with four 3,500kW diesel-electric main engines and two Azipod type propulsion motors. Four sea ice trials were carried out to understand the relationship between the engine power and the ship speed, given the Arctic ice condition. The analysis shows that the ARAON was able to operate at 1.5knots in a 2.5m thick medium ice floe condition with the engine power of 5MW, and the speed reached 3.1 knots at the same ice floe condition when the power increased to 6.6MW. She showed a good performance of speed in medium ice floe compared to the speed performance in level ice. More detailed analysis is summarized in this paper.