共查询到20条相似文献,搜索用时 46 毫秒
1.
Prediction of Stabilization of Ship in Random Wave 总被引:1,自引:0,他引:1
ZHANG Hai-peng LAI Zhi-chang JIN Hong-zhang LI Guo-binAutomation College Harbin Engineering University Harbin China 《船舶与海洋工程学报》2002,1(1):69-72
In this paper we show thc method of energy in part with which we can get the model of random wave,and predict theroll motion of unstabilized ship and stabilized ship using the wave model.The control parameters of fin stabilizer are determinedaccording to the performance index. The simulation of the system is also made in this paper. The comparison of the simulationwith real ship indicates that the method can be used in the prediction of roll motion of a stabilized ship in random wave. 相似文献
2.
WangJian 《中国远洋航务公告》2003,(3):40-42
So-called integrators are a new breed in the international freight transportation industry. Express carriers used to take small packages and envelopes fastest from one customer to another. The transport of documents are giving way to electronic data transfer, but the key essence of the express business, moving goods from door to door fastest 相似文献
3.
YukioMasuda 《中国远洋航务公告》2003,(12):52-53
I have been in oil and gas business, orthe evergy business in Japan for almost40 years at Mitsubishi Corporation. I hope myfew words will be a useful contribution totoday‘s agenda“Energy Security in Asia“and“Energy and Environment“. 相似文献
4.
From 1949 to the early 1970s, China was almost a self-sufficient economy, and invested little in transportation infrastructure. “Ihe average invesmaent in transpotation was about 3 percent of ttxal investment (China Statistical Yearbook 1991, 133). “Ihe kilometers of rail tracks barely doubled, the amount of Oared reads increased by only 1.3 times and only thirty new port berths were built. Conversely, freight volumes grew by 21, 34, and 31 times in rail, motor, and waterway, 相似文献
5.
LIU Ya-dong LI Ji-de LI ZhenCollege of Shipbuilding Engineering Harbin Engineering University Harbin China 《船舶与海洋工程学报》2002,1(2):6-11
In this paper a 3-D panoramic simulation system of a ship is described which is developed with the MAXSCRTPT language and VC + + as programming tools on the platform of 3 Dsmax. The strip theory method is applied to the motion prediction of the mono-hull. The time history solutions of heave and pitch are obtained in the condition of head sea to provide the primary data on panoramic simulation. The simulation system has following functions: 1) digital simulation; 2 ) panoramic simulation; 3) environmental set-up; 4) render preview and output. 相似文献
6.
ZHANG Ming-jun ZHENG Jin-xing ZHANG Jing College of Mechanical Electrical Engineering Harbin Engineering University Harbin China College of Computer Information Science Harbin Engineering University Harbin China 《船舶与海洋工程学报》2002,1(1):81-86
To research the effect of the selection method of multi-objects genetic algorithm problem on optimizing result, thismethod is analyzed theoretically and discussed by using an autonomous underwater vehicle(AUV) as an object. A changingweight vtlue method is put forward and a selection formula is modified. Some experiments were implemented on an AUV.TwinBurger. The results shows that this method is effective and feasible. 相似文献
7.
Strategies of state and local government in management of urban transport problems – A case of Delhi
In India, different layers of Government control different policy instruments to tackle transport externalities which might result in coordination problems and possible efficiency losses. This paper, therefore, addresses the coordination problem resulting from the division of policy instruments between two different government levels that face different types of externalities in varying degrees of magnitude in the urban transport sector by developing three types of theoretical models: the Full Control Centralised Model where the state government has full control over all pricing instrument; a Nash equilibrium model where each of the government levels controls only one instrument and takes the behaviour of the other as given; and a Stackelberg equilibrium mode where the behaviour of the state government is influenced by the fact that one of the price instruments is controlled by the local government. With an empirical illustration of the model for Delhi, the paper finds that since there are many interactions and many externalities between the two levels of government, a division of roles between them does not guarantee an efficient pricing outcome and the efficiency of pricing would depend on the institutional set up and on the correspondence between the objective functions of the two government levels. 相似文献
8.
YUFei SUNFeng 《船舶与海洋工程学报》2005,4(1):50-53
In this paper , the principle of H∞ filtering is discussed and H∞ filter is constructed, which is used in the initial alignment of the strapdown inertial navigation systems(SINS). The error model of SINS is derived. By utilizing constructed H∞ filter, the filtering calculation to that system has been conducted. The simulation results of the misalignment angle are given under the condition of unknown noises. The results show that the process of alignment with H∞ filter is much faster and with excellent robustness. 相似文献
9.
1INTRODUCTION Initialalignmentisoneofthekeytechnologiesof strapdowninertialnavigationsystem.Itdirectlyinflu encesthenavigationperformancesofthenavigation system.TheKalmanfilterhasbeenwidelyusedinthe initialalignmentofthestrapdowninertialnavigation systemwhichassumesthatbothdynamicsofsignalgen eratingprocessesandthestatisticalpropertiesofnoise sourceshavebeenknowninadvance.Insomeapplica tions,however,thedesignerisfacedwithmodelun certaintiesandlackofstatisticalinformationontheex ogenoussig… 相似文献
10.
11.
Daniel Puente-Rodríguez 《Coastal management》2013,41(5):426-446
Participation (e.g., stakeholder involvement) has become a central concept in the practice of environmental and coastal zone management. Research has shown that the integration of participation in coastal zone management has positive ecological and social outcomes. In the literature, however, participation is often reported in an unstructured and uncritical manner. Therefore, to find out whether and how there is a useful way to structure and characterize the way the coastal zone management literature deals with participation, we have conducted a literature review. The review was conducted and the literature structured through three central dimensions of participation, namely: power, knowledge, and (visions of) nature. The article concludes that this structured approach to participation enables us to study more systematically the role of participation and might facilitate the governance and learning processes of coastal networks. 相似文献
12.
In the present study an attempt has been made toinvestigate the relationship between the variations in the foulingassemblage and corrosion behaviour of HSLA steel at three coastallocations in the Gulf of Marmar, India, over a period of 24 months.Oyster fouling was dominant in the Tuticorin open sea, whilebarnacles were the major foulants in the Tuticorin harbour andMandapam. The fouling load in the Tuticorin waters was higherwhen compared to the Mandapam waters. The corrosion ratesdecreased progressively with the immersion time at all three testlocations. In the Tuticorin open sea, the corrosion rates were higherwhen compared to the other two locations throughout the studyperiod. The surface of the coupons was characterized by crevicesbeneath the hard foulers in the Tuticorin harbour and Mandapam,whereas in the Tuticorin open sea, the coupons experiencedcrevices of a tunneling nature. The percentage of the loss of thetensile strength increased with time at all the test locations. 相似文献
13.
LI Qing-fen WANG Peng REN Zheng-yi and LONG Ping School of Mechanical & Electrical Engineering Harbin Engineering University Harbin China 《船舶与海洋工程学报》2003,2(2):1-4
In this paper, the effect of plastic constraint on the initiation of ductile tears in four different shipbuilding structural steels has been experimentally studied by measuring the J-integral and crack opening displacement COD at initiation in three-point bend specimens with deep and shallow notches. Experimental results of seven groups of different strength alloy steels show that both Si and Ji values of ductile tear from the shallow crack specimens which have less constraint flow field are significantly higher than those of deeply notched specimens. Slip-line-field analysis shows that, for shallow crack, the hydrostatic stress is lower than that from standard deeply cracked bend specimen, which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structural defects, especially if initiation values of COD and J-integral are used. 相似文献
14.
DANG Kun SUN Pei-ting XIAO Jing-kun SONG Yong-xin 《船舶与海洋工程学报》2006,5(4):58-61
In order to verify the effectiveness of electrolytic treatment on ships' ballast water, experiments are carried out by a pilot system in laboratory. The raw seawater and seawater with different concentrations of different algae are simulated as ships' ballast water. The algae in the raw seawater can be killed if it is treated by electrolysis with an initial residual chlorine concentration of 5 mg/L. If the seawater with one kind of algae (Nitzschia closterum, Dicrateria spp., or Pyramidomonnas sp.105cells/mL) is treated by electrolysis with an initial residual chlorine concentration of 5 mg/L the alga can be sterilized, If the seawater with one kind of algae (Dunaliella sp., Platymonas or Chlorella spp.) is directly treated by electrolyzing with an initial residual chlorine concentration of 4 mg/L, the instant mortality changes with the concentration of different algae. However, after 72 hours, in all treated samples, there are no live algal cells found. 相似文献
15.
《船舶与海洋工程学报》2008,(3)
As a new type of hull form,trimaran has remarkable excellent performances and has drawn more and more attention.When the viscous CFD technology now available is applied to the research of resistance performance of trimaran,the spatial discretization would usually result in the grid error and uncertainty,and thus the considerable discrepancy between the numerical results and the experimental data.In order to ascertain how much the grid would affect the calculation,the grid convergence should be studied.A mathematical trimaran was chosen as an example,with the commercial code CFX for the simulation,VOF for surface treatment,and the grid study was carried out based on two different turbulence models.It was concluded that carrying out grid study is helpful in estimating the grid error and uncertainty,and indicating the direction of improving the credibility of the numerical calculation, and,in addition to grid errors and uncertainties,the turbulence modeling errors and uncertainties contribute to the simulation errors. 相似文献
16.
DANG Kun SUN Pei-ting XIAO Jing-kun and SONG Yong-xin . Marine Engineering College Dalian Maritime University Dalian China . Environmental Science Technology College Dalian Maritime University Dalian China 《船舶与海洋工程学报》2006,(4)
1 Introduction1 The introduction of invasive marine species into new environments by ships’ ballast water, attached to ships’ hulls and via other vectors, has been identified by the Global Environment Facility (GEF) as one of the four greatest threats t… 相似文献
17.
Nie Wu 《船舶与海洋工程学报》2002,1(2):28-32
Having carried out investigations on ship collision accidents with bridges in waterway in China, a database of ship collision with bridge (SCB) is developed in this paper. It includes detailed information about more than 200 accidents near ship' s waterways in the last four decades, in which ships collided with the bridges. Based on the information a statistical analysis is presented tentatively. The increase in frequency of ship collision with bridges appears, and the accident quantity of the barge system is more than that of single ship. The main reason of all the factors for ship collision with bridge is the human errors, which takes up 70%. The quantity of the accidents happened during flooding period shows over 3 - 6 times compared with the period from March to June in a year. The probability follows the normal distribution according to statistical analysis. Visibility, span between piers also have an effect on the frequency of the accidents. 相似文献
18.
JanuszMindykowski XUXiao-yan 《上海海运学院学报》2004,25(1):12-18
The paper deals with the selected problems of electric power quality in ships‘ modern systems.In the introduction the fundamentals of electric power quality assessment, such as the relations and consequences among power quality phenomena and indices, secondly as the methods and tools as well as the appropriate instrumentation, have been shortly presented. Afterwards, the basic characteristic of power systems on modern ships has been given. The main focus of the paper is put on the assessment of electric power quality in ships‘ systems fitted with converter subsystems. The state of the art and actual tendencies in the discussed matter have been shown. Some chosen experimental results, based on the research carried out under supervision of the author, have been presented, too. Finally, some concluding issues have been shortly commented on. 相似文献
19.
Research on the coefficient of sound absorption in turbid water 总被引:2,自引:0,他引:2
China’s coastal waters are turbid and the properties of the seabed are complex. This negatively impacts the performance of underwater detection equipment. The properties of sound absorption in turbid water are not well understood. In this paper, the coefficient of sound absorption in turbid water was measured by the reverberation technique. All work was done in a reverberation barrel made of seamless aluminum. First, pure water was poured into the reverberation barrel and its reverberation time measured. Next, various concentrations of turbid water were poured into the barrel and their reverberation time measured. After all data had been gathered, the coefficient of sound absorption in turbid water of different concentrations was calculated. From this we determined a law of sound absorption in turbid water as summarized in the paper. 相似文献
20.
In recent years, the dynamic responses of flexible risers have been the focus of many researchers. Most flexible risers undergo a substantial level of irregular motion from environmental loadings, which involves a continuous slip of helical wires. The slip of helical wires especially leads to a hysteretic effect by reducing the bending stiffness, making it hard to predict the dynamic responses of flexible risers. The current study, as an extension to Part I, presents a new large-scale dynamic analysis method for flexible risers. The suggested method creates a large-scale model for the dynamic analysis that considers a geometric and bending nonlinearity of flexible risers. The kinematics of each beam element is formulated based on a Green-Lagrangian strain and the interaction with the seabed, providing a realistic analysis of flexible risers. In particular, the current study introduces a direct moment correction method that modifies the internal force vector using an improved analytical model. The improved analytical model is assigned at each node of the large-scale model and estimates an accurate bending hysteresis curve considering the effect of shear deformation and varying tension. The suggested method corrects the bending moment and shear force of all beam elements based on the bending hysteresis curves obtained from the improved analytical model, by which a complex bending behavior of flexible risers is reflected in a large-scale domain. As a result, this study achieves a more accurate prediction of the dynamic responses and fatigue damage of flexible risers. A new dynamic analysis program, called OPFLEX, is developed herein based on the suggested analysis method. Using the developed program, the current study conducts several numerical investigations to identify the effect of the shear deformation and varying tension. Consequently, it is confirmed that the shear deformation of internal layers reduces the fatigue damage of helical wires by delaying the increase of internal stress. It is also identified that the effect of varying tension deteriorates the fatigue life of flexible risers through a continuous change of contact pressure during bending. 相似文献