保证耐波性能的目标函数的Wigley船型优化(英文)

The research performed in this paper was carried out to investigate the computational procedure to design seakeeping optimized ship hull form. To reach the optimized hull form, four stages should be done, which consists of: generate alternative hull form, seakeeping calculations, objective functions and optimization techniques. There are many parameters that may be determined in ship hull form optimization. This paper deals with developed strip theory for determining the seakeeping performance, genetic algorithm(GA) as optimization method, high order equations for curve fitting of the hull form and finally reaching to the minimum bow vertical motion in regular head waves. The Wigley hull is selected as an initial hull and carried to be optimized. Two cases are considered. For the first case, the only form coefficients of the hull(C B, C M, C W, C P) are changed and main dimensions(L, B, T) are fixed. In the second case both hull form and main dimensions are varied simultaneously. Finally, optimized hull form and its seakeeping performances are presented. The results of optimization procedure demonstrate that the optimized hull forms yield a reduction in vertical motion and acceleration.     

基于参数化CAD模型的船型阻力/耐波性一体化设计

在舰船概念设计阶段,往往需要快速生成阻力和耐波性能兼优的船型。采用基于母型船的船型融合生成方法,实现了参数化船型自动生成。在此基础上,采用iSight优化平台,将参数化船型生成技术与阻力、耐波性计算模型集成,运用多学科设计优化技术实现了船型阻力/耐波性性能一体化设计。优化方法采用多目标遗传算法以获取Pareto前沿。以一艘46 000 DWT油船的型线优化为算例对这个过程进行了具体说明,试验结果表明总阻力降低了3%,验证了这种方法的可行性。     

船载养殖水体纵摇运动下流场特性数值分析

发展以大型游弋式养殖工船可为深蓝渔业提供新的养殖手段。本文基于STAR-CCM数值计算软件研究了纵摇运动下养殖液舱内流场特性和壁面压力,建立了养殖液舱内适渔性的评估方法。典型海况中船舶纵摇运动对养殖液舱中流场的影响研究表明：当养殖液舱纵摇频率一定时,液舱内流速及壁面压力随纵摇幅值增大而增大；当养殖液舱纵摇与养殖水体发生共振时,液舱内流速及壁面压力急剧增大,对养殖对象安全及结构强度均有较大不利影响。对于海上养殖工船的养殖安全运行,选择风浪流条件合适的渔场,结合船体耐波性研究,优化船体型线,调节养殖舱水体固有频率,避开共振运动,是养殖工船适渔性研究的一个重要方向。     

Forecasting fishing vessel responses in coastal areas

A system for forecasting the operability of ships was developed by extending a wave forecasting system with the ship responses to the forecast sea states. The system produces 4-day wave forecasts in an implementation for the Portuguese Exclusive Economic Zone, where the vessels’ seakeeping performance is forecast, although the method presented could well be applied to any other coastal region. The proposed procedure requires the knowledge of the transfer functions for different ship speeds and headings. The computations are made for two different types of fishing vessels that currently operate in the Portuguese coast. Ship motions and derived responses are evaluated with a strip theory code and compared with the prescribed values of relevant seakeeping criteria that represent the limit conditions that still allow standard operational conditions for those vessels. For each forecast sea state at each grid point at a given time, the response spectrum is calculated and operability indexes are computed and compared with the maximum allowed values for a specific operation criterion. The results are presented as operational index maps for various areas of the Portuguese coast, and the information provided by system will help ship masters to plan the operation of their ships, namely to decide the areas to operate in anticipation. In this way, they can identify areas in which the level of operationally of their ships will be degraded due to weather conditions and avoid them.     

波浪引起破损船的垂向运动和弯矩（英文）

The wave-induced vertical ship motions and bending moments of a double hull-oil tanker in realistic flooding conditions are studied. The scenarios investigated are represented by water ingress into the starboard ballast tanks for collision damage cases and both starboard and portside ballast tanks for grounding situations. Seakeeping computations are performed for eight damage scenarios and for the intact condition, each corresponding to different changes in displacement, trim, and heel. For each of the damage conditions, transfer functions of vertical motions and loads are calculated using a potential linear 3 D panel hydrodynamic code in the frequency domain that includes effect of the motion of the water in flooded tanks. A MATLAB code is developed to facilitate automated hydrodynamic simulation of many damage scenarios. Verification of seakeeping results is performed by comparing transfer functions with results of the previous study. Wave-induced vertical responses of damaged ship are then compared to those of intact ship using two spectral-based methods originating from uncertainty analysis of wave loads, which are convenient tools to assess consequences of damage on short-term ship responses. Generally, observed trend is that vertical wave-induced responses of damaged ship converge toward those of intact ship with increasing wave period. Fairly small differences between responses of asymmetrically damaged ship with respect to the symmetrical incoming wave directions are found. The results of the study are an efficient method for seakeeping assessment of damaged oil tankers and the framework for evaluating consequences of damage scenarios, heading angles, and sea conditions on seakeeping responses of damaged ships.The results can be used to decide if the intact ship model can be used instead of the damaged one for the emergency response procedure or for the risk assessment studies when modeling and computational time represent important limitations.     

船舶耐波性与船舶航速

通过对耐波性的分析,总结了船舶在波浪中航行时的耐波性标准,并提出了船舶在考虑了耐波性标准后应采取的经济航速,为船舶在大风浪中的开航安全评估提供了依据。     

风浪中船舶航行安全性研究

依据船舶耐波性理论计算结果,运用灰色关联综合评估理论对大风浪中船舶耐波性进行了综合评估,然后根据评估结果确定船舶在波浪中以某一航速航行时的优选航向,并通过实例应用与分析表明,使用该方法能为船舶安全航行提供科学指导。     

基于灰评估的船舶航向优选方法研究

依据船舶耐波性理论计算结果,运用灰色关联综合评估理论对大风浪中船舶耐波性进行了综合评估,然后根据评估结果确定船舶在波浪中以某一航速航行时的优选航向,并通过实例应用与分析表明,使用该方法能为船舶安全航行提供科学指导。     

水面舰船迎浪航行时大幅运动预报的切片算法

将预报船舶运动和波浪载荷的切片理论加以扩展，应用于有限深水中船舶迎浪航行时大幅纵向运动和波浪载荷的时域求解。预报结果体现出考虑了湿表面及化后引起的船舶运动和受力的非线性性质。本计算方法简便、实用，适用于船舶纵向大幅运动预报。     

小水线面双体船在波浪中的运动响应预报

用切片理论方法发展了SWATH船耐波性预报程序，提供了390t方案的油田小水线面交通船计算分析结果，包括规则波中纵向运动频率响应函数的计算及不规则波中各种海况下的运动有义值预报。     

船体变形对主机轴承负荷影响的近似计算

营运船舶因外来原因造成船体变形,导致主机EB2和EB3轴承失去负荷且损坏轴瓦的事故,自20世纪70年代以来,一直受到各船级社和船舶设计和建造的研究部门重视。NK船级社在传统轴系校中时使用支反力影响数并引入了作用于机舱后舱舱壁处的当量支反力影响数,据此近似计算出在船体变形情况下,主机EB2和EB3轴承失去负荷的机舱后舱舱壁处的相对位移量。该量化指标使设计人员在轴系校中计算中加深了对船体变形的理解。     

渔船稳性衡准分析与算法研究

我国有数量庞大的渔业船舶,其稳性对船舶安全生产、船型设计开发等方面产生重要影响。本文整理现行渔业船舶稳性衡准要求;分析稳性衡准数的数理实质;进而应用国内外普遍认可的总体设计软件NAPA进行渔业船舶稳性衡准数核算方法研究开发。有助于提高对渔业船舶稳性的认知水平和校核能力,亦可为具备类似衡准要求的其他船型设计研发及稳性校核工具开发提供借鉴。     

基于S7-300PLC和PPU的远洋渔船船舶电站控制系统设计

基于S7-300可编程逻辑控制器(PLC)和船舶电站发电机并车与保护单元(PPU),设计了远洋渔船船舶电站智能化控制系统。以PLC为主站、PPU为从站组成的联合控制核心,采集发电柴油机组以及船舶电网的各项参数,实现输入、输出共享,并根据设置的参数进行智能化指令执行。满足船舶电站自动控制以及安全保护等功能,适应渔船在航行及作业过程中工况多变的特点,从而提高船舶电力网的可靠性、便利性与经济性。     

舰船大风浪中航行最大允许航速计算模式研究

舰艇在大风浪中航行,当航向已定时如何确定最大允许航速是航海界关注的课题。本文采用CFD(计算流体力学)方法和耐波性理论相结合的新模式,分别研究了浪增阻、风增阻及螺旋桨推力损失的计算方法,给出了比较精确的舰艇大风浪航行时的船体负载。在此基础上,运用船—机—桨理论,解决了最大允许航速(轮转速)的求解问题。     

高速深V型小艇耐波性试验研究

深V型艇与传统圆舭型小艇相比,在耐波性能上有较大改善。文章通过8.5 m小艇模型试验和实艇耐波性试验,系统研究了艇型V度对阻力的影响和横剖面形状对耐波性的影响,研究结果显示:对于载荷较重和航速较低的排水型船,若采用极深V型艇,可以同时获得更好的推进性能和耐波性。     

舰船回转过程中内、外侧螺旋桨负荷变化规律的新现象

在许多教科书中,螺旋桨推进双桨船在回转过程中内、外螺旋桨负荷变化规律均有如下叙述:回转过程中内侧螺旋桨负荷远大于外侧螺旋桨负荷.这个结论也被某些实船试验结果所证实.但新近完成的某双桨船的回转试验的多个实测结果表明:外侧螺旋桨负荷远大于内侧螺旋桨负荷.在上世纪90年代国内有人已发现过这一新现象,但当时无人记录和分析以进行研究.本文报告和分析了这一新现象.文章首先简要回顾了以往教科书和某些实船试航回转过程中内、外桨负荷变化规律;然后介绍了某新船回转试验的实测结果,论述了实测结果的可信性.本文着重探讨了导致这一新现象的主要原因,如船体形状、船的运动、内外螺旋桨的运动、桨与船的相互作用和桨与桨的相互作用等.     

远海作业锚泊定位大型抓斗船时域耦合分析

在环境复杂、作业水深较大的远海开敞海域进行作业时,大型抓斗船需采用锚泊定位方式,且船体运动响应受风浪影响较大。同时,在抓斗提升和旋转过程中,抓斗运动速度快,提升质量大,抓斗出水时全船所受载荷发生瞬时变化,加上复杂环境载荷的作用,对船舶安全具有很大影响。以适用于远海开敞海域、采用锚泊定位方式的200m3级大型抓斗疏浚船为研究对象,建立了船舶的水动力计算模型,对其运动响应RAO和载荷RAO进行了计算分析。考虑船舶主体、抓斗及锚泊系统之间耦合作用的影响,对抓斗作业时提升和旋转过程中船舶运动响应和锚泊线张力进行时域动力分析,得到了该船动力载荷结果,为后续的设计工作提供基础。     

Impact scenario models for probabilistic risk-based design for ship–ship collision

A number of authors have proposed probabilistic risk based ship design for ship–ship collision, conditional to the local trading area of a vessel. The probability of collision and consequences are determined based on the traffic conditions in which a vessel is expected to operate. This paper investigates the adequacy of currently available models for impact scenarios, i.e. models linking the traffic conditions to the conditions at the moment of collision. An exploratory statistical model is presented to establish such a link. A probabilistic risk based design case study is performed for a fleet of RoPax vessels trading on a specified route in the Gulf of Finland. The available impact scenario models from the literature are compared with the developed probabilistic evasive maneuvering model. The results show that the impact scenario models have a very significant influence to the calculated hull breach probabilities. No well-justified impact scenario models are presently available and also the presented probabilistic evasive maneuvering model is burdened with uncertainty. Hence, to move toward a probabilistic risk based ship design paradigm for ship–ship collision in a local trading area, more focus and research is needed to establish a credible link.     

基于三维势流理论的耐波性数值预报

准确预报船体运动响应对于砰击等波浪载荷的计算以及合理结构设计具有重要意义。船舶在大幅波浪中的运动呈明显的非线性,而现阶段耐波性预报多采用线性切片方法。三维水动力分析软件 WASIM基于时域势流理论,采用 Rankine面元法预报船舶在波浪中的运动响应,并考虑了多种非线性因素。本文以标模 DTMB5512为对象,采用 WASIM预报其在不同航速下的耐波性,并与基于线性切片理论的计算结果和模型试验结果进行对比。结果表明：利用 WASIM计算得到的船体运动响应比其他方法更接近试验值,合理体现了船舶在风浪中的实际耐波性能。因此,利用 WASIM能够较好地评估船舶在波浪中的非线性耐波特性。     

海上长球首尾双体风电维护船阻力和耐波性能研究

近年来,海上风电场迅猛发展,风电维护船成为迫切需求。借鉴小水线面双体船优良的阻力性能和穿浪双体船优秀的耐波性能,根据中国海上风电场维护船航行的环境和使用特点,选用阻力和耐波性能优良的长球首尾双体船型作为风电场维护船型。在此基础上采用CFD数值仿真计算阻力性能,运用NAPA软件计算耐波性能。从而得到不同条件下较优良的船型,为海上风电维护船的设计提供一定的参考和借鉴。