Parametric estimation of ship maneuvering motion with integral sample structure for identification     

《Applied Ocean Research》2015

This documentation presents the parametric identification modeling of ship maneuvering motion with integral sample structure for identification (ISSI) and Euler sample structure for identification (ESSI) based on least square support vector machines (LS-SVM), where ISSI is used for the construction of in–out sample pairs. By using Mariner Class Vessel, the sample dataset are obtained from 15°/15° zigzag maneuvering simulation based on Abkowitz model. By analyzing the simulation data including rudder angle, surge velocity, sway velocity, yaw rate and so forth, the hydrodynamic derivatives in Abkowitz model are all identified. The validation of the proposed identification algorithm is verified by the high precisions of the identified hydrodynamic derivatives and maneuvering prediction results. The comparison is also conducted between the proposed ISSI and the conventional Euler sample structure for identification (ESSI), and the experimental results shows that ISSI is much more appropriate for parametric identification modeling of ship maneuvering motion.  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   

Ship performance monitoring dedicated to biofouling analysis: Development on a small size research catamaran     

《Applied Ocean Research》2019

  相似文献   

论渔业法之对影响渔业船舶适航行为的法律责任          下载免费PDF全文

张安琪  裴兆斌 《海洋开发与管理》2020,37(9):31-34

渔船管理是渔业产业管理的重要内容,而船舶适航性是渔船正常运行的重要保证。我国现阶段渔业产业中出现的船舶事故频发,其中很多是不适航导致的。文章从我国渔业监管现状出发,结合《渔业法》及其相关法律对影响船舶适航行为法律责任的相关规定,分析违法行为构成要件,发现依然存在处罚手段单一、处罚力度不够等问题,针对存在的原因,从完善对相关违法行为的认定,加强行政监管,丰富处罚方式,提高行政处罚标准等措施出发提出完善建议,从而减少渔业安全事故,推动我国渔业健康发展。  相似文献   

Application of potential flow methods to fast displacement ships at transcritical speeds in shallow water     

《Applied Ocean Research》2018

Computer codes implementing three different numerical methods for the prediction of ship squat at transcritical speeds in shallow open-water are tested. SlenderFlow is a potential flow code specifically for ships in very shallow water, based on partially dispersive slender body theory. Flotilla is a potential flow code based on fully dispersive thin-ship theory. Rapid is a general nonlinear free-surface panel code. Code predictions of transcritical sinkage, trim and resistance in laterally unrestricted water were compared to the experimental results of Graff (1964) for two Taylor series hulls in a finite-width towing tank. Once tank width effects were accounted for, each of the three codes was found to give good predictions within the valid range of the underlying theory. A simple method for estimating transcritical wave resistance from trim is presented.  相似文献   

基于AIS的船舶会遇局面紧迫度量化分析   总被引：1，自引：0，他引：1  

欧阳知雨  张安民  张永兵 《海洋通报》2019,38(2):225-232

近年来船舶大型化、高速化的发展以及数量的不断递增,导致船舶碰撞概率大大增加。为更好地保障船舶航行安全,提出船舶会遇局面紧迫度这一概念。该概念表征船舶在当前航行状态下由于一定范围内所有其他船舶的存在而处于的会遇局面的紧迫程度,其旨在帮助船舶驾驶员实时感知并掌握船舶在海上航行时所处会遇局面的状况,从而据此加以判断并及时采取措施规避碰撞风险。建立了船舶会遇局面紧迫度的计算模型,该模型以考虑到本船速度的动态圆形领域为空间约束条件,综合考虑其他船舶相对于本船的方位分布和距离这两个指标的影响,基于信息量量化紧迫度。利用2016年1月1日天津港AIS数据进行紧迫度的计算与分析,计算结果与实际相符,该计算模型能够准确反映船舶在航行过程中所处会遇局面的紧迫程度。利用双线性内插法建立天津港区域紧迫度二维彩色平面分布图,其表达效果优于传统热度图。  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