• Journal of the Society of Naval Architects of Korea
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• v.51 no.6
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• pp.489-494
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• 2014

Estimation of correct ice load under various operating conditions is important during the design and the operation stages of an icebreaker. Normal operating conditions are expected from the official field ice trials and also from general ice transit action. In this paper ice load for the Korean icebreaking research vessel, ARAON, under normal operating condition, is discussed. Published ice load data from full-scale sea trials of six icebreakers were analysed to derive an empirical ice load prediction formula. The IBRV ARAON had sea ice trials during 2010 and 2012 summer season. Strain gauge signal were recorded during her icebreaking voyage and the measured strain data were converted to the equivalent hull stress values. The effect of ARAON's speed in ice and the hull stresses are investigated. By comparing the empirical formula and ice load calculation based von measured data, it is recommended to use the empirical ice load estimation formula for the initial design stage.

• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.468-473
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• 2016

This paper focuses on the estimation of local ice loads exerted from ship-ice interaction processes. The Korean IBRV ARAON was used to perform field ice trials during her 2015 Arctic voyage. During ARAON's general ice transit, a total of 72 channels of data from both strain gauges on the inner hull plates and those installed on the transverse frames of the ARAON's bow section structures were analyzed to calculate the local ice loads. The local ice loads estimated from the analysis of the shear strain data measured on the side frames were compared to those from the hull plate pressures.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.529-535
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• 2016

This study focuses on the comparison of measured data from 6-DOF motion sensor and strain gauge installed in the IBRV ARAON during 2015 summer voyage in the Arctic. Procedures to calculate the global ice load from MotionPak II inertial measurement system and the local load from stain gauge system are discussed. The ship's speed and peak load are determined in the concept of an ice collision "event". It is found that the peak values in the global ice calculated form whole ship motion analysis fall in the range of 1.5~3 times of the local ice load based in strain gauge measurement.

• Journal of Ocean Engineering and Technology
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• v.26 no.1
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• pp.1-8
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• 2012

To correctly estimate ice load and ice resistance for a ship's hull, it is essential to understand the material properties of sea ice during ice field trials and to use the proper experimental procedure for gathering ice strength data. The first Korean-made icebreaking research vessel (IBRV), ARAON, had her second sea ice trial in the Arctic Ocean during July and August of 2010. This paper describes the test procedures used to properly obtain sea ice strength data, which provides the basic information on the ship's performance in an ice-covered sea and can be used to estimate the correct ice load and ice resistance on the IBRV ARAON. The data gathered from three sea ice field trials during the Arctic voyage of the ARAON includes the ice compressive strength, flexural strength, and failure strain of sea ice. This paper analyzes the gathered sea ice data in comparison with data from the first voyage of the ARAON during her Antarctic Sea ice trial in January 2010.

• Journal of Ocean Engineering and Technology
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• v.33 no.2
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• pp.161-167
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• 2019

This paper focuses on a newly designed ice load formula based on the ARAON's 2016 Arctic field data in order to improve a structural design against ice loads. The strain gage signals from ARAON's hull plating were converted to the local ice pressure upon the hull plating using the influence coefficient matrix and finite element analysis. First, a traditional pressure-area relationship is derived by applying probabilistic approaches to handle the strains measured onboard the ARAON. Then, the local ice load prediction formula is re-analyzed after reviewing the ARAON's additional field data to consider information about the ship speed and thickness of the sea ice. It is shown that the newly developed pressure-area relationship well reflects the influence of other design parameters such as the ship speed and ice thickness in the prediction of local ice loads on Arctic vessels.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.5
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• pp.330-338
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• 2021

This paper focuses on the improvement of the influence coefficient matrix method for estimation of local ice load on the icebreaking research vessel ARAON. The influence coefficient matrix relates ice pressure on the hull plate to the measured/calculated hull strain/stress. Conventionally von Mises equivalent stresses representing hull stresses and ice pressure acting on the hull plate are utilized to assemble the influence coefficient matrix. Because of the three dimensional features of the ship-ice collision process, an enhanced method to assemble the influence coefficient matrix is derived considering ice loads in the X, Y, and Z direction simultaneously. Furthermore the location of ice loads acting on hull-plate may fall outside the measuring sensor area, and the enhanced influence coefficient matrix is modified to reduce the difference between the actual and the estimated ice loads by expanding the domain outward from the sensor area. The developed method for enhanced influence coefficient matrix is applied to IBRV ARAON during the 2019 Antarctic ice field test and the local ice loads in three directions are efficiently calculated compared to those by a conventional method.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.3
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• pp.186-197
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• 2015

In summer 2010, field measurements of local ice loads were carried out in the Arctic Ocean using the Korean first icebreaking research vessel, ARAON. In some previous studies by the authors, several investigations for the data measured at 2010 including the relationship between the measuring points and ice loads, the possibility for observation of higher ice load and the relationship between the ship speed and ice loads were reported. During 10 days in August 2013, new field measurements were performed in similar waters of the Arctic Ocean using the same vessel, ARAON. The aim of this study is to investigate the statistical properties of 2013 measurements and compare results by two periods.

• Journal of Ocean Engineering and Technology
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• v.27 no.5
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• pp.88-92
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• 2013

The icebreaking research vessel (IBRV) ARAON had her second ice trial in the Arctic Ocean in the summer season of 2010. During the voyage, the local ice loads acting on the bow of the port side were measured using 14 strain gauges. These measurements were carried out in three icebreaking performance tests. To convert the measured strains into the local ice pressures, a finite element model of the instrumented area was developed. The influence coefficient method (ICM), which uses the influence coefficient from the finite element model, and the direct method, which uses the measured strain, were selected as the conversion methods. As a result, the maximum measured pressure was 1.236MPa, and the average difference between ICM and the direct method was about 5% for an area of $0.2m^2$. The pressure-area relationship of the measurement falls below the range of the existing pressure-area curve, which is due to the low ice strength of melted ice in the summer.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.421-425
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• 2018

The icebreaking research vessel ARAON performed ice field tests during her 2016 Arctic voyage. The ship is subjected to ice loads through ice-ship interaction processes. Local ice load acting on ARAON's bow section was measured by using stain gauges installed on the inner hull plates and transverse frames of bow section. In this paper the local ice loads at transverse frames estimated from shear strain data were compared to ice loads from hull plate pressures by using the influence coefficient method. In addition to the analysis of local ice loads, the characteristics of peak ice loads with the ship speed is also discussed. It is recommended that the local ice loads estimated by calculating shear forces acting on transverse frames may be useful in estimating local ice loads on the hull of ship.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.254-258
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• 2014

Field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. To correctly estimate ice load and ice resistance on ship's hull, It is essential to understand the material properties of sea ice during ice field trials and to perform the proper experimental procedure by gathering sea ice data. A measurement of sea ice properties was conducted during February and March of 2012 with the Korean Icebreaking research vessel "ARAON" in the Amundsen Sea, Antarctica. This paper describes a test procedure to obtain sea ice data which provide basic information to estimate ice loads and icebreaking performance of the ship. The data gathered from sea ice field trials during the 2012 Antarctic voyage of the ARAON includes ice temperature/salinity/density and the compressive/flexural strength of sea ice. This paper analyses the gathered Antarctic sea ice material properties comparing with the previous data obtained during ARAON's Arctic and Antarctic voyages in 2010.