基于互联网的船舶机桨匹配远程计算平台

为满足远程船舶机桨匹配设计的需求,结合MATLAB和C#平台进行混合编程,运用Easyui进行用户交互界面设计,介绍一套基于互联网的B/S架构船舶机桨匹配远程计算平台。在该平台上通过船舶机桨匹配中的初级匹配、终结匹配和空泡校核等3个实例进行平台测试。测试结果表明,该平台操作简单、计算速度快、结果准确,能很好地实现远程机桨匹配计算,可为未来船舶动力系统工况在线监测及"互联网+"环境下的机桨动态匹配提供工程基础。     

机桨匹配初步设计软件实现方法研究

研究现有机桨匹配初步设计软件设计方法及其存在缺点,提出正确实现机桨匹配初步设计软件思路和实现方法.该方法从初步设计概念出发,搜索满足机桨匹配且效率最高的桨及对应主机,可用于绘制船舶一定航速下,定桨径不同转速及不同桨径最佳转速机桨匹配分析曲线.变换不同航速,还可得到完整的分析图谱.     

船机桨工况匹配与船舶节能

介绍了船机桨之间的相互制约及其工况匹配,从而证实了船机桨工况最优匹配与船舶节约燃料的密切关系。     

内河多工况船机桨匹配优化设计

[目的]内河船舶在航行时存在顺水、逆水和急流等多种工况,传统的内河船舶船?机?桨匹配设计方法仅对船舶在逆水上行时进行了匹配设计,而在顺水下行工况,因船舶推进效率低、主机利用率低,造成油耗成本高、经济性较差等,因此需进行多工况内河船舶船?机?桨匹配优化设计.[方法]首先,在不同工况下对内河船舶推进系统的各参数进行设计,并...     

基于遗传算法的船舶推进系统船、机、桨匹配云平台设计

随着海上运输业的蓬勃发展,船舶的航行速度、吨位和功率不断增长,船机桨匹配越来越受到造船业的重视。船机桨之间的完美匹配有利于提高推进系统的功率和航行速度,降低船舶油耗,增加航行时间。本文在分析船舶航行过程中船体阻力特性和螺旋桨推进特性的基础上,设计船机桨匹配设计方案,建立合适的目标函数,并利用遗传算法进行船机桨参数优化计算。实验结果表明,遗传算法计算精度高,收敛速度快。     

污底对拖网渔船的影响分析

本文根据污底的生长特点,从船舶阻力和船机桨匹配两方面,结合了渔船的工作特点,详细分析了污底对拖网渔船的影响。污底增加不但会增加船舶阻力,同时还会对船舶推进性能产生负面影响,最终加剧了拖网渔船船机桨不匹配状况。     

船、机、桨动力耦合可视化系统设计与实现

为了实现船、机、桨之间匹配关系的可视化及实现MATLAB在船舶动力系统计算中的应用,基于船、机、桨动力匹配关系,利用向量计算方法在Simulink平台设计了一套船、机、桨瞬态仿真系统,并在MATLAB GUI中设计了可视化仿真控制台.系统中,基于S函数对Simulink模块进行了二次开发,增强了数值关系的表现效果.仿真系统正确地预测了船、机、桨匹配中各个参数的变化趋势,并且可有效地帮助轮机管理人员理解船、机、桨之间的复杂耦合关系.     

混合推进船舶"船-泵+桨-机"匹配方法研究

为提高混合推进船舶推进系统的性能,分析了"船-泵+桨-机"的匹配方法.介绍了"船-桨-机"与"船-泵-机"的匹配方法、思路与步骤,着重研究"船-泵+桨-机"匹配中的泵、桨负载分配对推进性能的影响.以调距桨特性曲线与喷水推进推力曲线进行混合推进舰船的快速性计算,螺旋桨重载降低推进效率,喷水推进重载容易产生空化.为避免喷水推进泵产生空化,调距桨的螺距、转速可调范围变窄.     

船舶主推进系统机桨匹配设计工况的优化选择

将航行工况和机桨匹配同时考虑 ,建立了船舶主推进系统机桨匹配设计工况的优化选择模型 ,分析了其不同的应用情况 ,并应用于实船修理中 ,取得了明显的效益。     

吊舱式电力推进船舶螺旋桨匹配设计仿真研究

在国内,吊舱推进器的设计还处于理论起步阶段,尤其是吊舱推进器螺旋桨,其设计方法尚未成熟,而螺旋桨的设计对于整个推进系统推进性能的影响又尤为关键,关系到船—机—桨匹配的综合推进性能。为此,采用常规螺旋桨敞水特性图谱等效设计POD螺旋桨参数的方法对吊舱推进器螺旋桨进行设计,分析吊舱式推进船舶船—机—桨的匹配性能。为了提高设计效率及优化推进系统的推进性能,针对吊舱式电力推进船舶,采用常规螺旋桨等效设计方法设计POD螺旋桨参数,同时基于LabVIEW图形化编程语言开发船—机—桨匹配数值分析软件以对设计参数进行静态匹配计算,并与母船的推进效率进行对比,选取最优化的螺旋桨参数作为POD螺旋桨参数,以优化推进效率。研究结果表明：采用常规螺旋桨等效设计方法设计POD螺旋桨参数的方案,同时结合开发的船—机—桨匹配数值仿真分析平台,可以方便、快捷地对吊舱式推进船舶进行船—机—桨匹配分析计算比较,提高推进性能。     

船行波对双船系靠LNG泊位系泊稳定性的影响

双船系靠LNG泊位对系泊稳定性要求高,而目前尚无船行波对双船系靠泊稳定性影响的定量分析方法。结合工程实例,以Flory-Remery单船系泊船行波荷载计算方法为基础,结合双船系靠泊位的特点予以修正,利用数值分析软件定量分析船行波过程对双船系靠泊位系泊稳定性的动态影响。结果表明,典型系泊条件下,双船系靠泊位系泊倒缆受力及纵移运动量受船行波影响最大,当船行波与系泊船间距50 m时系泊稳定性不满足要求;当船行波与系泊船间距100 m时系泊稳定性满足要求;当船行波与系泊船间距150 m时系泊稳定性基本不受船行波影响。     

Analysis of ship–ship collision damage accounting for bow and side deformation interaction

This paper presents a procedure to analyse ship collisions using a simplified analytical method by taking into account the interaction between the deformation on the striking and the struck ships. Numerical simulations using the finite element software LS-DYNA are conducted to produce virtual experimental data for several ship collision scenarios. The numerical results are used to validate the method. The contributions to the total resistance from all structural components of the collided ships are analysed in the numerical simulation and the simplified method. Three types of collisions were identified based on the relative resistance of one ship to the other. They are denoted Collision Types 1 and 2, in which a relatively rigid ship collides with a deformable ship, and Collision Type 3, in which two deformable ships are involved. For Collision Types 1 and 2, estimates of the energy absorbed by the damaged ships differ by less than 8% compared to the numerical results. For Collision Type 3, the results differ by approximately 13%. The simplified method is applicable for right angle ship collision scenario, and it can be used as an alternative tool because it quickly generates acceptable results.     

Optimal portfolio choice for ship leasing investments

ABSTRACT

We develop an advanced portfolio analysis method to determine the optimal ship mix for a portfolio. A typical business model of a ship leasing firm is to acquire ships for charter income. However, transportation assets (such as ships and aircraft) are different from financial assets (e.g. stocks and bonds) as they are tangible and have a limited useful life. Thus, methodologies for financial portfolios cannot be simply extended to portfolios of transportation assets. Recently, ship leasing represents a non-traditional source of ship finance. A ship leasing firm can manage a certain number of ships across different ship types. Based on portfolio theory and industry-related evidence, we construct an optimal ship portfolio consisting of a manageable combination of carefully chosen ships. The expected return of the asset combination is examined with respect to various ship types and sizes. We quantify the freight risk for different categories of ships in different sectors to investigate the characteristics of ship portfolios. The estimation of such freight risk is of considerable interest to academics and practitioners alike, because determining the behaviour of freight risk has important implications for investment decisions regarding ships. Our portfolio method should strongly support the decision-making process involved in leasing ships.     

Duration analysis for recurrent ship accidents

About 63% of the world’s shipping accidents are recurrent—they occur to ships that have already experienced at least one prior accident. Therefore, reducing recurrent accidents can contribute significantly to maritime safety. We study the factors affecting both first and recurrent accidents, by focusing on the duration between two accidents. Cox proportional hazard models are applied to ship accident data from 1996 to 2015, and the results identify which ships have a high risk of recurrent accidents, based on ship attributes, ship supply and market conditions, shipbuilding country, previous accident type, and ship type. The recurrent rate is high when the ship involved in the accident is old, small, flies a flag of convenience, and has no detention record. In addition, the accident risk increases when the shipping market faces a high bunker price, overcapacity in supply, a high time charter rate, or low newbuilding price. On the other hand, ships built in China and Japan have lower recurrent accident rates than those built elsewhere, although ships built in China have earlier first accidents than do others. General cargo ships have the highest recurrent accident rate, followed by dry bulkers, container ships, and tankers, in that order.     

中小型集装箱船方形系数估算公式

在所收集的近百艘中小型集装箱船船型资料的基础上,作者对集装箱船方形系数与载箱数、傅汝德数的关系作了分析,并应用计算机回归得到一个能反映集装箱船特征的方形系数估算公式。此公式可应用于集装箱船的初步设计阶段。     

船型标准化率对三峡船闸实际通过能力的影响

推进船型标准化是提高三峡船闸实际通过能力的有效途径之一。为定量研究船型标准化程度对船闸实际通过能力的提升效果,在研究三峡库区船舶过闸流程的基础上采用系统仿真方法构建三峡库区船舶过闸仿真模型,模拟不同船型标准化率下三峡船闸的实际通过能力。仿真试验结果表明:仿真模型可以真实地反映三峡库区船舶过闸情况;船型标准化率达到90%以上时,标准船型对提升船闸运行效率的优势凸显。相比于对船闸实际通过能力的提升,船型标准化率的提高对船舶过闸服务质量的改善更为显著。     

船舶无人化后对船舶设计的影响因素分析

从船舶无人化后的特点出发,对现有船舶设计需遵守的国际公约进行分析,指出无人船设计应继续遵守或无需遵守的公约条例。从船舶设计角度着手遵照船舶设计螺旋线,系统分析无人船设计过程中应该考虑的各种因素,并对影响较显著的船舶空船重量、船体设计形式、船舶主机选型、总布置设计与船舶建造成本等进行了详细的论述,为以后无人船设计及新船型开发打下基础。     

补给作业船舷侧碰撞损伤环境研究

基于横向补给作业中各个阶段可能出现的舷侧碰撞模式所确定的两船碰撞发生时的夹角和补给作业船受撞位置,进行横向补给作业船舷侧碰撞损伤仿真研究。分析了补给作业船的吸能特性和碰撞过程中两船的运动状态,获得了碰撞力、能量吸收和损伤变形的时序结果。该文的研究可对于开展补给作业船舷侧碰撞结构损伤评估、舷侧抗撞结构的优化设计提供指导。     

船行波对复式航道隔离带宽度的影响

复式航道是根据船舶吃水的不同将航道断面设计为深浅不同的阶梯形。由于小船的耐波性较差,大船航行时所兴起的船行波往往会引发小船横摇角的显著增大,影响安全。设计时可将两航道间留有一定的富裕距离（隔离带）,以减少船行波的影响。通过数值计算和物理模型试验两种方法,分析研究了不同参数条件下,船行波对小船横摇角的影响,由此判断隔离带宽度能否满足要求。     

船体腐蚀对船舶强度的影响

基于营运船的船体腐蚀状况,运用船体剖面模数概念,分析了船体腐蚀对船舶强度的影响,提出了一些保证船舶强度的措施,为船舶的保养工作提供参考,以减少船舶安全事故的发生.