适应南海开发与保护需求的船舶装备思考          下载免费PDF全文

张铮铮  石亚军 《海洋开发与管理》2016,33(2):43-47

三沙市设立以来,其建设与发展迎来了前所未有的新契机。由于其特殊的自然环境,船舶装备建设无疑是"建设三沙、发展三沙"的核心环节之一。文章对三沙市船舶装备的发展需求进行了分析,介绍了其发展现状,并给出其建设的体系图,旨为三沙市船舶装备建设提供参考。  相似文献   

Effect of ship structure and size on grounding and collision damage distributions     

P. Terndrup Pedersen  Shengming Zhang 《Ocean Engineering》2000,27(11)

It has been argued that a major shortcoming in the International Maritime Organization (IMO) Interim Guidelines for Approval of Alternative Methods of Design and Construction of Oil Tankers in Collision and Grounding is that grounding and collision damages normalized by the main dimensions of the ship have the same probability density distributions regardless of a particular structural design and ship size.The present paper explores analytical methods for assessing the overall effect of structural design on the damage distributions in accidental grounding and collisions. The results are expressed in simple expressions involving structural dimensions and the building material of the ships. The study shows that the density distribution for collision and grounding damages normalized by the main dimensions of the ship depends on the size of the ship. A larger ship has a higher probability of a larger relative damage length than that of a smaller ship in grounding damage. On the other hand, the damages to the side structure caused by ship collisions are found to be relatively smaller for large ships.The main conclusion is that the existing IMO damage distributions will severely underestimate the grounding damages to the bottom structure of larger vessels and to a lesser extent overestimate collision damages to the side structure of the hull.  相似文献   

Finite element analysis of ship structures using a new stiffened plate element   总被引：2，自引：0，他引：2  

Y. V. Satish Kumar  M. Mukhopadhyay   《Applied Ocean Research》2000,22(6):361-374

A new stiffened plate element is developed for the three-dimensional finite element analysis of ship structures. The plate element can accommodate any number of arbitrarily oriented stiffeners and obviates the use of mesh lines along the stiffeners. The new element provides a very economic global analysis of the complete ship structure with fewer elements and without any loss of accuracy. The global analysis of a rectangular box shaped vessel is carried out with the present element and compared with the general-purpose finite element software NISA. An Offshore Tug/Supply Vessel is analysed for crest at perpendiculars.  相似文献   

Improved prediction of the threshold of surf-riding of a ship in steep following seas     

Wan Wu  Kostas J. Spyrou 《Ocean Engineering》2010,37(13):1103-1110

An extended version of Melnikov's method is implemented in order to predict more accurately the threshold of global surf-riding for a ship operating in steep following seas. The key advantage of the proposed method is that it overcomes the limitation of small damping and/or small forcing that are intrinsic to the implementation of the standard Melnikov's method. A reference ITTC ship is used here by way of example and the result is compared to that obtained from standard analysis as well as numerical simulations. Because of the primary drawback of the extended Melnikov's method is the inability to arrive at a closed form equation, in this work the authors arrive at a “best fit” approximation to the extended Melnikov numerically predicted result.  相似文献   

Lower bound limit loads of ship structure components using the m_α-tangent method based on single linear elastic analysis     

S.L. Mahmood  R. Seshadri 《Ocean Engineering》2010,37(13):1139-1148

Limit loads for ship structure components are determined in this paper based on a single linear elastic finite element analysis by invoking the concept of kinematically active reference volume in conjunction with the m_α-tangent method. The method enables rapid determination of lower bound limit loads for ship structure components by taking their kinematically inactive volume into consideration. This method is applied to a number of ship structure components possessing different percentages of inactive volume. Results are compared with the corresponding inelastic finite element results, and available analytical solutions.  相似文献   

The simulation of the geometry of a tuna purse seine under current and drift of purse seiner   总被引：4，自引：0，他引：4  

Yong-Hae Kim  Myeong-Chul Park 《Ocean Engineering》2009,36(14):1080-1088

It was necessary to obtain a more practical interactive precise model of the three-dimensional (3-D) geometry during purse seine operations considering movements of fishing vessel and details of the sea condition. The changes in the shape of a purse seine from shooting to pursing during pelagic skipjack fishing was recorded in the Southwest Pacific Ocean by photographs of the scanning sonar with in situ measurements of water flow by a current meter. The modeling of 3-D geometry during purse seining was established using finite element methods, as resultant force vector from flow drag, buoyancy, sinking force, tension of pulling or pursing acting on net panels in connection with drift of fishing vessel with time elapsed from the start of shooting to the end of pursing. The simulation results were matched closely by field measurements as a heart-like shape in upper net near floatline and a water-drop shape in purse line following drift of ship towards inside net circle during pursing. This model of a purse seine can be extended to almost any kind of purse seine generating real fishing parameters and to modeling fish capture process.  相似文献   

A nonlinear model of parametric rolling stabilization by anti-roll tanks     

Marcelo A.S. Neves  Jorge A. Merino  Claudio A. Rodríguez 《Ocean Engineering》2009,36(14):1048-1059

The present paper describes a mathematical model in which the fluid motion inside a U-tank is nonlinearly coupled to the heave, roll and pitch motions of the ship. The main purpose of the investigation is centred on the control of roll motion in the case of parametric resonance in longitudinal waves. A transom stern small vessel, known to be quite prone to parametric amplification, is employed in the study. Four tank designs are employed in order to study the influence of tank mass, tank natural frequency and tank internal damping on the control of parametric rolling at different head seas conditions. Additionally, the influence of the vertical position of the tank is also investigated. The main results are presented in the form of limits of stability, with encounter frequency and wave amplitudes as parameters. Distinct dynamical characteristics are discussed and conclusions are drawn on the relevant parameters for the efficient control of the roll amplifications in head seas.  相似文献   

Modal analysis of a fast patrol boat made of composite material     

F.M. Santos  C. Guedes Soares 《Ocean Engineering》2009,36(2):179-192

The structural dynamic behaviour of a fast patrol boat is studied with two- and three-dimensional idealizations for dry-hull analysis. A preliminary two-dimensional beam analysis is conducted by means of the Prohl-Myklestad method to derive a first estimate of the first four symmetric mode shapes. A more complex three-dimensional finite element model is developed in order to evaluate the modal characteristics for both symmetric and coupled anti-symmetric distortions, with the emphasis placed on the former.  相似文献   

Investigation of ship hydroelasticity     

Ivo  &#x;ime  Stipe 《Ocean Engineering》2008,35(5-6):523-535

The importance of hydroelastic analysis of large and flexible container ships of today is pointed out. A methodology for investigation of this challenging phenomenon is drawn up and a mathematical model is worked out. It includes definition of ship geometry, mass distribution, structure stiffness, and combines ship hydrostatics, hydrodynamics, wave load, ship motion and vibrations. Based on the presented theory, a computer program is developed and applied for hydroelastic analysis of a flexible segmented barge for which model test results of motion and distortion in waves have been available. A correlation analysis of numerical simulation and measured response shows quite good agreement of the transfer functions for heave, pitch, roll, vertical and horizontal bending and torsion. The tool checked in such a way can be further used for reliable hydroelastic analysis of ship-like structures.  相似文献   

On the parametric rolling of ships using a numerical simulation method   总被引：2，自引：0，他引：2  

B.C. Chang   《Ocean Engineering》2008,35(5-6):447-457

This paper has shown a numerical motion simulation method which can be employed to study on parametric rolling of ships in a seaway. The method takes account of the main nonlinear terms in the rolling equation which stabilize parametric rolling, including the nonlinear shape of the righting arm curve, nonlinear damping and cross coupling among all 6 degrees of freedom. For the heave, pitch, sway and yaw motions, the method uses response amplitude operators determined by means of the strip method, whereas the roll and surge motions of the ship are simulated, using nonlinear motion equations coupled with the other 4 degrees of freedom. For computing righting arms in seaways, Grim's effective wave concept is used. Using these transfer functions of effective wave together with the heave and pitch transfer functions, the mean ship immersion, its trim and the effective regular wave height are computed for every time step during the simulation. The righting arm is interpolated from tables, computed before starting the simulation, depending on these three quantities and the heel angle. The nonlinear damping moment and the effect of bilge keels are also taken into account. The numerical simulation tool has shown to be able to model the basic mechanism of parametric rolling motions. Some main characteristics of parametric rolling of ships in a seaway can be good reproduced by means of the method. Comprehensive parametric analyses on parametric rolling amplitude in regular waves have been carried out, with that the complicated parametric rolling phenomena can be understood better.  相似文献