• 한국해양공학회지
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• 제9권1호
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• pp.36-46
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• 1995

빙판파괴 형태는 여러 모드의 합성이며 실제로 한 가지 양식으로 파괴되는 경우는 거의 일어나지 않는다. 이제까지 빙하중 해석 이론이나 방법은 한 가지 양식에 기준하는 것이었다. 이 논문에서는 합성모드로 빙판이 파괴될 때 해양구조물에 작용하는 빙하중 추정방법을 소개하여 모형 실험결과치와 그 결과를 비교하였다. 두 가지 합성모드에 대한 빙하중 추정방법인 비례파괴해석법 (Proportional Failure Method)과 국부경계해석법(Local Ice boundary Method)을 본논문에 소개하였으며, 이 두가지 방법과 함께 널리 알려진 Crushing 해석방법을 적용하여 정적 및 동적 구조물에 작용하는 빙하중을 산출/비교하였다. 동적구조물은 쇄빙선을 이용하였고, 쇄빙선이 SPM 터미널에 monopod로 연결되어있는 형태를 선택하였다. 모형 실험은 Finland의 Wartsila 실험실에서 실시 하였고, 이 실험을 통하여 쇄빙선에 작용하는 빙력 및 시간별 쇄빙선의 동적 움직임을 측정하였다. 이 논문에서는 위에서 소개된 세가지 방법으로 계산된 빙하중과 실험측정결과를 비교하였고, 이론적으로 추정한 쇄빙선의 운동을 실혐결과치와 비교하였다. Crushing방법으로 산출한 빙하중은 실제치보다 상당히 높았고, 비례파괴해석법은 Crushing 방법보다 정확한 결과를 보여주었으며, 국부경계해석법은 상당히 모형실험측정치와 가까웠다. 물론 쇄빙선의 움직임도 빙하중에 따라 변화가 심했고, 국부 경계해석법을 적용했을 때 실제 쇄빙선의 동적움직임을 가장 가깝게 추정할 수 있었다.

• 전산구조공학
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• 제6권1호
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• pp.39-43
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• 1993

본문에 열거한 빙하중의 산정방법을 비교해 볼 때, 구조물의 규모가 크고 다년생 얼음이 설계하중으로 작용하는 경우 에너지 평형 방법 중 소성 극한이론을 근거로 한 Korzhavin식을 이용하는 것이 타당하리라 판단된다. 극한 응력에 의한 방법은 구조물의 직경이 작은 경우에 완전 관입이 되는 것을 가정하기 때문에 직경이 큰 구조물에서는 빙하중의 크기가 과대 평가될 가능성이 크며, 극한 하중에 의한 방법은 Ridge Building Force의 부정확성 때문에 쉽게 적용하기 곤란하여 이에 대한 통계적 자료가 크게 요구된다. 지반과 구조물의 유연성을 고려한 동적 모델에 의한 방법은 참고문헌을 소개하는 것으로 대신한다.

• 한국항해항만학회지
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• 제37권2호
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• pp.143-148
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• 2013

본 연구의 목적은 빙해역을 운항하는 선박의 쇄빙시 깨진 해빙에 의해 선수부 좌현 외판에 작용하는 국부 빙하중을 계측한 신호의 특성을 조사하는 것이다. 한국 최초의 쇄빙연구선인 아라온호를 이용하여 2010년 8월초 북극해에서 실선 시험을 수행하여 선수부에 설치된 변형률 게이지로부터 국부적인 빙하중에 의한 신호를 계측하였다. 국부적인 빙하중에 의한 구조 응답 특성을 반영한 계측 신호는 전형적인 유체 충격압에 대한 하중-시간 이력과 다소 다른 특성을 갖는 것도 있음이 파악되었다. 본 연구에서는 계측 신호에 대한 시간 이력을 분석하고, 무차원화된 특성값들로 나타내었다.

• 한국해양공학회지
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• 제29권1호
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• pp.28-33
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• 2015

The icebreaking research vessel ARAON had her second ice trial in the Arctic Ocean from July 16 to August 12, 2010. In this study, the ice loads measured during the “general” operation and “ice breaking” operation in ice-covered waters were analyzed and compared. Whereas the “general” operation stands for the voyage in the water partially covered by ice, the “ice breaking” operation involved substantial ice floes for the ice breaking performance test. Based on the measured data, comparisons of the relationship between the ship speed and ice load, and between the locations of strain gauges and ice loads were investigated. Peak stresses higher than 20 MPa were found. The longitudinal and vertical correlations between the measurement location and ice load were analyzed, and the probability of peak stress was calculated. As a result, the probability function for higher ice loads during both operation modes was expressed in an exponential and power forms.

• 대한조선학회논문집
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• 제51권2호
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• pp.107-113
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• 2014

The icebreaking research vessel, ARAON had her second ice trial in the Arctic Sea from 16th July to 12th August 2010. During the voyage, the local ice loads acting on the bow of port side were measured from 14 strain gauges. The measurements were also carried out in ice waters with various ice concentration ratio as well as the icebreaking performance tests. In this study, the ice loads measured during the 'general' operation in ice waters were analyzed. As a first step, the relationship between the location of strain gauges and the ice loads were investigated, and then the possibility for observation of higher ice loads was estimated based on the probability density function. The relationship between the ship speed and the ice load was also investigated. 718 peak stresses data higher than 20 MPa obtained from strain gauges array attached in longitudinally and vertically was analyzed. In general, the ice load increases as the ship speed increases in the low ship speed range, and ice load decreases as the ship speed is greater than a certain speed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.69-70
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• 2016

선박과 유빙의 충돌로 발생하는 빙하중은 선체의 구조강도 문제뿐만 아니라 선박의 속력감소 및 조종운동에도 영향을 미친다. 이 연구에서는 DEM (Discrete Element Method) 기법을 이용하여 유빙을 항해하는 선박의 조종성능 평가를 위한 수치 시뮬레이션 프로그램을 개발한다. 여러가지 유빙 조건에서 선회성 시험 및 10/10 지그재그 시험을 시뮬레이션하여, 유빙의 상태가 선박의 조종성능에 미치는 영향을 파악한다.

• 한국해양공학회지
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• 제32권6호
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• pp.411-418
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• 2018

This paper introduces a new method of ice load generation in the time domain for the station-keeping performance evaluation of Arctic offshore structures. This method is based on the ice load spectrum and mean ice load. Recently, there has been increasing interest in Arctic offshore technology for the exploration and exploitation of the Arctic region because of the better accessibility to the Arctic ocean provided by the global warming effect. It is essential to consider the ice load during the development of an Arctic offshore structure. In particular, when designing a station-keeping system for an Arctic offshore structure, a consideration of the ice load acting on the vessel in the time domain is essential to ensure its safety and security. Several methods have been developed to consider the ice load in the time domain. However, most of the developed methods are computationally heavy because they consider every ice floe in the sea ice field to calculate the ice load acting on the vessel. In this study, a new approach to generate the ice load in the time domain with computational efficiency was suggested, and its feasibility was examined. The ice load spectrum and mean ice load were acquired from a numerical analysis with GPU-event mechanics (GEM) software, and the ice load with the varying heading of a vessel was reconstructed to show the feasibility of the proposed method.

• 대한조선학회논문집
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• 제45권2호
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• pp.175-185
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• 2008

One of the concerns that arise during navigation in ice-covered waters is the magnitude of ice loads encountered by ships. However, the accurate estimation of ice loads still remains as a rather difficult task in the design of icebreaking vessels. This paper focuses on the development of simple ice load prediction formulas for the icebreaking cargo vessels. The maximum ice loads are expected from unbroken ice sheet and these loads are most likely to be concentrated at the bow area. Published ice load data for icebreaking vessels, from the model tests and also from full-scale sea trials, are collected and then several ice load prediction formulas are compared with these data. Finally, based on collected data, a semi-empirical ice load prediction formula is recommended for the icebreaking cargo vessels.

• 대한조선학회논문집
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• 제46권6호
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• pp.603-610
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• 2009

Ice load is one of the important design parameters for the construction of icebreaking vessels. In this paper, the design ice load prediction for the icebreaking vessels under normal operating condition in ice-covered sea is discussed. The ice loads under normal operating condition are expected from sea trials in moderate ice conditions. In this sense the extreme ice loads during heavy ramming or accidental collision are not considered. Current study describes the global ice load on the hull of the icebreaking vessels. Available ice load data from full-scale sea trials are collected and analyzed according to various ship-ice interaction parameters including displacement, stem angle, speed of a ship and flexural strength and thickness of sea ice. The ice load prediction formula is compared with the collected full-scale sea trials data and it shows a good agreement.

• 대한조선학회논문집
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• 제53권6호
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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.