检索结果-南通市图书馆

Discrete element modeling of ice loads on ship hulls in broken ice fields

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2013年第11期32卷 50-58页

作者： JI Shunying LI Zilin LI Chunhua SHANG Jie Department of Engineering Mechanics Dalian University of Technology National Marine Environment Forecasting Center State Oceanic Administration North China Sea Marine Forecasting Center North China Sea BranchState Oceanic Administration

ice loads on a ship hull affect the safety of the hull structure and the ship maneuvering performance in ice-covered regions. A discrete element method （DEM） is used to simulate the interaction between drifting ice floes and a moving ship. The pancake ice floes are modelled with three-dimensional （3-D） dilated disk elements considering the buoyancy, drag force and additional mass induced by the current. The ship hull is modelled with 3D disks with overlaps. ice loads on the ship hull are determined through the contact detection between ice floe element and ship hull element and the contact force calculation. The influences of different ice conditions （current velocities and directions, ice thicknesses, concentrations and ice floe sizes） and ship speeds are also examined on the dynamic ice force. The simulated results are compared qualitatively well with the existing field data and other numerical results. This work can be helpful in the shil3 structure design and the navigation securitv in ice-covered fields.

关键词： ice load ship hull discrete element method broken ice

Uncertainty and joint probability of sea ice loads

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1995年第3期14卷 439-445页

作者： Liu Defu Yang Yongchun Wang Chao and Li Tongkui(Ocean University of Qingdao, Qingdao 266003, China)(Tianjin University, Tianjin 300072, China)(China Offshore Oil Design Engineering Corporation,Tianjin 300450, China)

ice load is one of the most important factors for design of marine stuctures in cold sea *** designcriteria of ice loads for marine structures consist of two parts: level ice thickness and crushing strength. Due to thestrong randomness of the affecting factors on ice thickness and crushing strength, such as ice temperature,air temperature, water temperature,salinity,wind field, numerical simulation method method can not produce satisfactory results. Thispaper proposes a method of uncertainty analysis and joint probabilistic prediction of level ice thickness and crushingstrength instead of traditional ice load criteria for marine structures.

关键词： ice load design criteria uncertainty analysis joint probability

Dynamic ice loads on conical structures

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2011年第2期1卷 65-67页

作者： Yan Huang~(a) and Xuehua Li School of Civil Engineering,Tianjin University,Tianjin 300072,China School of Civil Engineering Tianjin University Tianjin 300072 China

Two series of model tests were performed to observe the dynamic ice loads on conical *** variable testing parameters include the water line diameter of the model cone and ice *** small water line diameter tests,two-time breaking is found to be the typical failure of ice on steep conical structure,and also be controlled by other factors,such as ice speed and the cone *** big water line diameter tests,the ice sheet failed nonsimultaneously around the *** independent zones of bending were found in the nonsimultaneous failure process of *** the increase of the ratio of D/h and the number of independent zones,the total ice force was found being gradually reduced.

关键词： conical structure model test ice load

ice Induced Low Temperature Fatigue Crack Propagation in Offshore Structural Steel A131

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 1998年第3期13卷 275-284页

作者： Duan, ML Gao, ZJ Liu, CT China Classificat Soc Beijing 100006 Peoples R China Chinese Acad Sci Inst Mech Beijing 100080 Peoples R China

To investigate the low temperature fatigue crack propagation behavior of offshore structural steel A131 under random ice loading, three ice failure modes that are commonly present in the Bohai Gulf are simulated according to the vibration stress responses induced by real ice loading. The test data are processed by a universal software FCPUSL developed on the basis of the theory of fatigue crack propagation and statistics. The fundamental parameter controlling the fatigue crack propagation induced by random ice loading is determined to be the amplitude root mean square stress intensity factor K-arm. The test results are presented on the crack propagation diagram where the crack growth rate da/dN is described as the function of K-arm. It is evident that the ice failure modes have great influence on the fatigue crack propagation behavior of the steel in ice-induced vibration. However, some of the experimental phenomena and test results are hard to be physically explained at present. The work in this paper is an initial attempt to investigate the cause of collapse of offshore structures due to ice loading.

关键词： low temperature fatigue crack propagation offshore structure steel A131 ice load random vibration

An Integrated Approach to Fatigue Life Prediction of Whole System for Offshore Platforms

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2001年第2期16卷 177-184页

作者：方华灿段梦兰许发彦吴永宁樊晓东 University of Petroleum China Beijing 102200 China China Classification Society Beijing 100006 China Nanjing Hydraulic Research Institute Nanjing 210024 China Shanghai Of ffshore Petroleum Bureau Shanghai 200120 China

The failure of one or even more components usually does riot lead to the collapse of the whole structure. Most of the analysis of fatigue is centered on only a single component which the researchers are interested in or Much attention should be paid to. However, the collapse of a structure is the result of failure of a series of components in a specific order or path. This paper proposes an integrated approach to fatigue life prediction of whole structural system for offshore platforms, mainly describing the basic principles and prediction method. A method is presented for determining the failure path of the whole structure system and calculating the fatigue life in the determined failure path, The corresponding final collapse criteria for the whole structure system are discussed, A simple method of equivalent fatigue stress range calculation and a mathematical model of structural component fatigue life estimation in consideration of sea wave and sea ice loads are provided. As an application of the proposed approach, a fixed production platform Bohai No. 8 is chosen for the predication of fatigue life of the whole structure system by means of the software OSFAC developed based on the present methods.

关键词： fatigue cyclic stresses life prediction offshore platform ice load ice infested waters

Efficient Approximate Method of Global Reliability Analysis for Offshore Platforms in the ice Zone

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2008年第2期22卷 303-311页

作者：李刚张大勇岳前进 Eric C. Spurgeon State Key Laboratory of Structural Analysis of Industrial Equipment Dalian University of Technology Department of Civil and Environmental Engineering University of FloridaGainesville

ice load is the dominative load in the design of offshore platforms in the ice zone, and the extreme ice load is the key factor that affects the safety of platforms. The present paper studies the statistical properties of the global resistance and the extreme responses of the jacket platforms in Bahai Bay, considering the randomness of ice load, dead load, steel elastic modulus, yield strength and structural member dimensions. Then, based on the above results, an efficient approximate method of the global reliability analysis for the offshore platforms is proposed, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. Finally, numerical examples of JZ20-2 MSW, JZ20-2NW and JZ20-2 MUQ offshore jacket platforms in the Bahai Bay demonstrate the satisfying efficiency, accuracy and applicability of the proposed method.

关键词： offshore platform ice load reliability probability distribution

Modification Method of Longitudinal Bow Structure for ice-Strengthened Merchant Ship

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2022年第3期27卷 298-306页

作者： DING Shifeng ZHOU Li GU Yingjie ZHOU Yajun School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuChina Shanghai Rules and Research Institute China Classification SocietyShanghai 200135China

:Merchant ships,which are quite different from icebreakers,usually require the light ice-strengthened bow under the floe-ice *** to ice-class B,requirements of China Classification Society(CCS),intermediate frames and thick hull plates are necessary for the ice belt area to resist floe-ice ***,due to the limited space,it is not practical to set so many intermediate longitudinals from manufacture point of *** this paper,a modification method is proposed to solve the problem by maintaining the frame spacing and increasing the plate *** aim is to make sure that the bow owns the equivalent ice-bearing capacity with the original frame *** first,a bulk carrier with ice-class B is used for case *** to the requirements of the ice class rule,a designed ice thickness is used to calculate the ice load acting on the bow area due to the impact of ice *** structural models are presented to perform the strength analysis under ice load,including the out-shell plate model and the longitudinal *** results show that increasing the plate thickness is helpful to remove the negative effect induced by enlarging the spacing of the longitudinal.A reasonable curve is presented to modify the bow for the ice-strengthened merchant ship,which shows the relationship between the increase of plate thickness and the spacing of ***,a model test of floe-ice–ship interaction is conducted to measure the dynamic ice load,based on which nonlinear dynamic FE analysis is used to verify the presented plate-thickness–longitudinal spacing *** results show that the proposed method can be used to improve the ice-strengthened bow structure effectively,which provides theoretical foundation to modify the requirement of CCS’s ice class rule.

关键词： ice-strengthening ice load ice model test nonlinear FE method ice class rule