• Title/Summary/Keyword: Design ice load

Search Result 51, Processing Time 0.027 seconds

Estimation of the Fatigue Damage for an Ice-going Vessel under Broken Ice Condition Part II - Simplified Approach (유빙 하중을 받는 내빙 선박의 피로손상도 추정 Part II - 간이 해석법)

  • Kim, Jeong-Hwan;Kim, Yooil
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.56 no.3
    • /
    • pp.231-241
    • /
    • 2019
  • In this study, a simplified analysis method was developed to evaluate the fatigue damage of an ice-going ship under broken ice condition. The global ice load, which is essentially calculated at the design stage of the Arctic vessel, and the hull form information were used to estimate the local ice load acting on the outer-shell of the ship. The local ice load was applied to the finite element analysis model, and the Weibull parameters for the target fatigue point were derived. Finally, fatigue damage was evaluated by applying the S-N curve and the Palmgren-Miner rule. For the verification of the proposed method, numerical analyses using direct approach were performed for the same conditions. A numerical model that implements the interaction between ice and structure was introduced to verify the local ice load and the stress calculated from the proposed method. Finally, the fatigue analyses of the Baltic Sea for actual ice conditions were performed, and the results of the proposed method, the method using numerical analysis, and the LR method were compared.

An Estimation of Cooling Load for Control of Ice Storage System (빙축열 시스템의 제어를 위한 냉방부하 예측)

  • Yoo, Seong-Yeon;Han, Seung-Ho;No, Kwan-Jong;Lee, Je-Myo;Kang, Tae-Seok
    • Proceedings of the SAREK Conference
    • /
    • 2005.11a
    • /
    • pp.205-210
    • /
    • 2005
  • Ice storage system stores cold energy using ice, which is used for cooling on next day. Ice storage system is the effective cooling system that uses cheep electric energy during a night, and also suppresses the peak load of electricity. In this study, the normalized temperature, relative humidity and specific humidity are analyzed using the weather data for past five years in order to estimate the cooling load for the control of ice storage system. The calculated cooling loads show fairly good agreement with the measured data of model hospital, especially at the outdoor design temperature of $25^{\circ}C$.

  • PDF

Calculation of Fatigue Life of Bow Frame of ARAON Considering Navigating in Ice and Open Waters (빙 및 일반해역 운항을 고려한 아라온호 선수프레임의 피로수명 계산)

  • An, Woo-Seong;Lee, Tak-Kee;Hwang, Mi-Ran
    • Journal of Ocean Engineering and Technology
    • /
    • v.32 no.6
    • /
    • pp.458-465
    • /
    • 2018
  • Ice-going ships such as icebreakers, icebreaking tankers, and icebreaking LNG carriers are subjected to wave loads in open water and ice loads in ice-covered water. In terms of the ship's structural design, the local ice load is important. The fatigue failure due to repeated ice loads is also important. ISO 19906 specifies the assessment of the fatigue limit for a polar offshore structures. In addition, Lloyd's Register refers to fatigue damage based on ShipRight FDA ICE. In ShipRight FDA ICE, the fatigue damage indices due to wave and ice loads are simply presented as 0.5 for each load. It also states that the sum of the two fatigue damage indices should not exceed one. This study calculated and analyzed the fatigue damage index and fatigue life considering ARAON's voyage schedules and the assumed Antarctic voyage based on data measured during the Arctic voyage of ARAON in 2010.

Minimum life-cycle cost design of ice-resistant offshore platforms

  • Li, Gang;Zhang, Da-Yong;Yue, Qian-Jin
    • Structural Engineering and Mechanics
    • /
    • v.31 no.1
    • /
    • pp.11-24
    • /
    • 2009
  • In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both ice-resistant and economical offshore platforms. However, risk is involved in the design, construction, utilization, maintenance of offshore platforms as uncertain events may occur within the life-cycle of a platform under the extreme ice load. In this study, the optimum design model of the expected life-cycle cost for ice-resistant platforms based on cost-effectiveness criterion is proposed. Multiple performance demands of the structure, facilities and crew members, associated with the failure assessment criteria and evaluation functions of costs of construction, consequences of structural failure modes including damage, revenue loss, death and injury as well as discounting cost over time are considered. An efficient approximate method of the global reliability analysis for the offshore platforms is provided, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. The proposed life-cycle optimum design formula are applied to a typical ice-resistant platform in Bohai Bay, and the results demonstrate that the life-cycle cost-effective optimum design model is more rational compared to the conventional design.

The Study of Economical Efficiency for the Ice Storage System of more Energy Consumption Building (에너지 다소비형 건물 축냉 시스템의 경제성에 관한 연구)

  • Lee, Je-Myo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.24 no.10
    • /
    • pp.733-738
    • /
    • 2012
  • It is important issue to reduce the electric energy to save the operating cost of HVAC system. Even if electrical energy is the clean energy, it is difficult and takes high cost for storage of electricity. These cause the high peak load of electric energy for HVAC in summer season. In korea, government impose the electric charge with several grade for the purpose of cut-off the peak load of electricity. Government has a policy to support to design and install the heat/ice storage system using midnight electricity. In this study, analysis of cooling load and operating characteristics for ice storage system are performed. And, also economical efficiency is compared between ordinary charge system of electricity and midnight rate charge of electricity. The systematic and economical supports are needed for expansion of usage of energy saving equipments.

Control strategy for economic operation of an ice-storage system considering cooling load variation (냉방부하 변동을 고려한 빙축열시스템의 경제적 운전방식)

  • 정성훈;이대영;강병하;김우승
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.12 no.2
    • /
    • pp.140-149
    • /
    • 2000
  • A comparative analysis was peformed on the operation cost at partial loads between ice storage systems with the two conventional control strategies, i.e., storage priority and chiller priority. The storage priority control is shown to be more economic for small cooling loads, while the chiller priority control is superior when the cooling load is as large as the design value. Based on this finding, a new control strategy is devised for an ice-storage system to minimize the operation cost at any cooling load. The new control strategy is found to be comparable to the chiller priority for large cooling loads, while it is more economic for small loads compared to the conventional control strategies. The practicality of the new control strategy is also confirmed through a performance test applying the new control strategy to an existing ice-storage system.

  • PDF

Study on Ice Parameters Affecting DP Performance of FPSO in Arctic Ocean (극지용 FPSO의 DP 성능에 영향을 미치는 빙 파라미터 분석에 관한 연구)

  • Choi, Sol-Mi;Lee, Seung-Jae;Han, Solyoung;Lee, Jaeyong
    • Journal of Ocean Engineering and Technology
    • /
    • v.32 no.1
    • /
    • pp.43-50
    • /
    • 2018
  • Recently, various efforts have been made to develop oil and gas in the Arctic Ocean. It is very important to consider the load caused by ice in designing floating structures in the area. The magnitude of the ice load and its impact on a structure should be considered. In this paper, we analyze ice parameters affecting the DP performance of FPSO with a DP-assisted mooring system. Several ice characteristics are selected, and the resulting ice load is calculated using GEM software. Numerous simulations are conducted while changing the values of the parameters, and DP capability plots are generated to visualize the effects of changing these parameters. It is shown that the ice drift speed and thickness are the major properties to be considered in DP system design. The limitations of the analysis and future work are discussed in the conclusion.

Evaluation of the limit ice thickness for the hull of various Finnish-Swedish ice class vessels navigating in the Russian Arctic

  • Kujala, Pentti;Korgesaar, Mihkel;Kamarainen, Jorma
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.10 no.3
    • /
    • pp.376-384
    • /
    • 2018
  • Selection of suitable ice class for ships operation is an important but not simple task. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards such as Polar Code, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. This paper will analyse what can be the limiting ice thickness for ships navigating in the Russian Arctic and designed according to the Finnish-Swedish ice class rules. The permanent deformations of ice-strengthened shell structures for various ice classes is determined using MT Uikku as the typical size of a vessel navigating in ice. The ice load in various conditions is determined using the ARCDEV data from the winter 1998 as the basic database. By comparing the measured load in various ice conditions with the serviceability limit state of the structures, the limiting ice thickness for various ice classes is determined. The database for maximum loads includes 3-weeks ice load measurements during April 1998 on the Kara Sea mainly by icebreaker assistance. Gumbel 1 distribution is fitted on the measured 20 min maximum values and the data is divided into various classes using ship speed, ice thickness and ice concentration as the main parameters. Results encouragingly show that present designs are safer than assumed in the Polar Code suggesting that assisted operation in Arctic conditions is feasible in rougher conditions than indicated in the Polar Code.

Strength assessment method of ice-class propeller under the design ice load condition

  • Ye, L.Y.;Guo, C.Y.;Wang, C.;Wang, C.H.;Chang, X.
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.11 no.1
    • /
    • pp.542-552
    • /
    • 2019
  • The strength assessment is the most important part at the design of ice-class propeller. Based on ice rules for ice-class propeller in IACS URI3 and FEM, the strength assessment method of ice-class propeller is established in this paper. To avoid the multifarious meshing process of propeller blade, an automatic meshing method has been developed by dividing the propeller geometry into a number of 8-node hexahedron elements along radial, chordwise and thickness directions, then the loaded areas in five cases can easily be calculated and identified. The static FEM is applied to calculate the stress and deformation of propeller blade. The fair agreements between the results of the present method and ANSYS/Workbench demonstrate its robust and the feasibility, and also the method is able to produce smooth gradient field. The blade stress and deformation distributions for five load cases are studied, and then the strength of the whole blade is checked.

Study on Influence of Ship Speed on Local Ice Loads on Bow of the IBRV ARAON

  • Kim, Tae-Wook;Choi, Kyungsik;Lee, Jong-Hyun;Lee, Tak-Kee
    • Journal of Advanced Research in Ocean Engineering
    • /
    • v.1 no.1
    • /
    • pp.25-35
    • /
    • 2015
  • This study presents the analysis of relationship between ship speed and local ice load on the Korean Icebreaker ARAON. The relationship curves were made from the data obtained at two areas: the Arctic and the Antarctic; and for two operation condition: the icebreaking condition in sea ice trial and general operation in ice covered sea. The strain data were converted to the equivalent stress value, and the influence of ship speed on the local ice load was analyzed and compared each other. These analysis results are useful in working on a statistically valid hull design approach.