Influence of sway motion on passive anti-rolling tank

1Introduction Thepassiveanti rollingtankisoneoftheshipstabiliz erssuccessfullyusedallovertheworld.Itisapplicable toreducetherollingatanyspeed,especiallyfitsfor theshipsatlowspeedorzerospeed.Atpresent,the theoryaboutthepassiveanti rollingtankisfairlyma tur…     

深水二维对称式布置两成分锚泊线时域动力分析

深水作业海上浮式结构物的锚泊定位系统由锚链或锚索等成分进行约束,由于锚泊线的几何非线性,外界环境作用力的非线性和系泊浮体的运动的非线性给锚泊系统的回复力和位移的计算分析带来困难。此外,多种材料成分组成的多成分锚泊线的使用在推动了锚泊系统的深水应用和发展的同时也给锚泊系统的设计带来困难。本文采用设计波理论结合有限元方法进行两成分锚泊线的动力分析,考虑导缆孔处系泊结构物运动的影响。并将结果与单一成分锚泊线计算结果作比较分析,得到有益结论。     

The application of modeling and prediction with MRA wavelet network

As there are lots of non-linear systems in the real engineering, it is very important to do more researches on the modeling and prediction of non-llnear systems. Based on the muhi-resolution analysis (MRA) of wavelet theory, this paper combined the wavelet theory with neural network and established a MRA wavelet network with the scaling function and wavelet function as its neurons. From the analysis in the frequency domain, the results indicated that MRA wavelet network was better than other wavelet networks in the ability of approaching to the signals. An essential research was carried out on modeling and prediction with MRA wavelet network in the non-linear system. Using the lengthwise sway data received from the experiment of ship model, a model of offline prediction was estab lished and was applied to the short-time prediction of ship motion. The simulation results indicated that the forecasting model improved the prediction precision effectively, lengthened the forecasting time and had a better prediction results than that of AR linear model. The research indicates that it is feasible to use the MRA wavelet network in the short -time prediction of ship motion.     

大吨位平面转体连续梁桥转体施工和监控要点

桥梁平面转体施工是利用桥梁组成部分为转体结构,将支架预制拼装的梁体旋转安装到位,适用于跨越不间断交通的航道、铁路或公路的桥梁施工。为确保大吨位的平面转体桥转体的安全,转体时应对转体的落架、试转和正式转体中的各种参数进行监测控制。     

系泊系统非线性恢复力研究及其应用(英文)

Mooring system plays an important role in station keeping of floating offshore structures.Coupled analysis on mooring-buoy interactions has been increasingly studied in recent years.At present,chains and wire ropes are widely used in offshore engineering practice.On the basis of mooring line statics,an explicit formulation of single mooring chain/wire rope stiffness coefficients and mooring stiffness matrix of the mooring system were derived in this article,taking into account the horizontal restoring force,vertical restoring force and their coupling terms.The nonlinearity of mooring stiffness was analyzed,and the influences of various parameters,such as material,displacement,pre-tension and water depth,were investigated.Finally some application cases of the mooring stiffness in hydrodynamic calculation were presented.Data shows that this kind of stiffness can reckon in linear and nonlinear forces of mooring system.Also,the stiffness can be used in hydrodynamic analysis to get the eigenfrequency of slow drift motions.     

水翼艇纵向运动多变量随机最优控制仿真

基于随机控制理论，针对全浸式水翼艇的多变量随机控制方法进行探讨，并着重分析水翼艇的纵向运动姿态的随机最优控制。首先，依据动力学原理对其运动方程的建立和线性化进行了推导。其次，利用线性卡尔曼滤波器对其纵向运动姿态进行估计，依据LOG性能指标构造了最优控制规律。通过施加控制前后状态的比较，可以看出，应用随机最优控制的方法，对水翼艇的纵向运动进行控制取得了良好的效果。     

烟台港芝罘湾港区三突堤码头平面布置研究

烟台港芝罘湾港区紧邻烟台市城区,港口可用岸线将开发殆尽,仅存的二、三突堤之间1段岸线的开发利用显得尤为重要。从充分利用既有岸线,最大化增加陆域面积等方面,对烟台港芝罘湾港区三突堤码头平面布置进行研究。研究结果表明,采用形成陆域资源和码头岸线较多,且码头岸线较为顺直的方案最佳。     

水下目标双基阵纯方位跟踪性能分析

研究双基阵纯方位目标运动分析的基本原理和方法,给出卡尔曼滤波算法的模型,进行仿真实验,比较和分析了仿真结果。仿真结果表明,应用卡尔曼滤波可以快速、稳定地完成目标运动要素的估计,同时还分析了数据关联、基阵间距以及方位测量误差对跟踪性能的影响,为工程应用提供了参考。     

ATM安全协议分析

利用ATM做为下一代因特网传送骨干已成为技术发展之趋势,因此,ATM的安全问题日显突出。文章从ATM的网络安全的目标入手,对ATM安全协议的内容从用户平面安全服务和控制平面安全服务作了分析和研究。     

红外焦平面成像技术的军事应用与发展

国外红外焦平面成像技术在现代战争中发挥着越来越重要的作用。文章介绍了红外焦平面成像技术的发展历程以及装备的研制、改进情况,指出了在现代战争中发展红外焦平面成像技术的优势和重要性,重点探讨了几种红外焦平面成像技术的性能及其特点,最后论述了红外焦平面成像技术的发展动向与分析。