重力式深水网箱的抗台设计与水动力性能分析

针对重力式深水网箱抗台风能力较弱,容易出现浮架损坏、锚绳断裂和网衣严重变形等问题,以一典型重力式深水网箱为研究对象,结合传统网格式系泊,提出在底部附加系泊缆的新型抗台设计方案,基于势流理论和非线性有限元方法,建立网箱数值模型,在不同入射角和波高下,对比分析传统网格式和新型抗台式系泊的网箱系泊缆张力、浮架运动和网箱变形。数值计算结果表明:与传统网格式系泊相比,新型抗台式系泊的网箱水平偏移平均减小7.81%,垂直下沉增加59.71%,系泊缆最大张力降低26.61%,网箱体积剩余系数增加超过70%,明显高于网箱容积的破坏阈值。     

波浪和海流对浮式海洋牧场的作用（英文）

The paper is partly a review on hydrodynamic and structural aspects of fish farms. In addition, new numerical results are presented on the stochastic behavior of bending stresses in the floater of a realistic net cage in extreme wave conditions. The behavior of traditional-type fish farms with net cages and closed fish farms in waves and currents is discussed. Hydroelasticity can play a significant role for net cages and closed membrane-type fish farms. The many meshes in a net cage make CFD and complete structural modeling impracticable. As an example, a hydrodynamic screen model and structural truss elements are instead used to represent the hydrodynamic loading and the structural deformation of the net. In addition, the wake inside the net due to current plays an important role. The described simplified numerical method has been validated by comparing with model tests of mooring loads on a single net cage with two circular elastic floaters and bottom weight ring in waves and currents. It is discussed which parts of the complete system play the most important roles in accurately determining the mooring loads. Many realizations of a sea state are needed to obtain reliable estimates of extreme values in a stochastic sea. In reality, many net cages operate in close vicinity, which raises questions about spatial variations of the current and wave environment as well as hydrodynamic interaction between the net cages. Live fish touching the netting can have a non-negligible influence on the mooring loads. It is demonstrated by numerical calculations in waves and currents that a well boat at a net cage can have a significant influence on the mooring loads and the bending stresses in the floater. The latter results provide a rational way to obtain operational limits for a well boat at a fish farm. Sloshing has to be accounted for in describing the behavior of a closed fish farm when important wave frequencies are in the vicinity of natural sloshing frequencies. The structural flexibility has to be considered in determining the natural sloshing frequencies for a membrane-type closed fish farm. Free-surface non-linearities can matter for sloshing and can, for instance,result in swirling in a certain frequency domain for a closed cage with a vertical symmetry axis.     

Real-time estimation of riser's deformed shape using inclinometers and Extended Kalman Filter

The real-time monitoring of underwater risers, cables, and mooring lines by multiple sensors is in great demand but still very challenging. In this study, a new real-time riser monitoring method based on an Extended Kalman Filter (EKF) is proposed. It estimates the overall shape of riser in real-time utilizing the measured signals from multiple bi-axial (inclination and heading) inclinometers along the riser. The novel EKF algorithm is shown to be robust against sensor noises and successfully reproduces the actual riser profiles at each time step, which has been verified by multiple tests through numerical simulations. For verification, a turret-moored FPSO (Floating Production Storage and Offloading) with a SCR (Steel Catenary Riser) is employed in four different random waves and currents. Subsequent algorithms are also developed so that the corresponding bending and axial stresses along the riser can also be estimated in real time from the obtained riser shape, which can further be used for the real-time estimation of fatigue-damage accumulation.     

Numerical modelling of hydrodynamic responses of Ocean Farm 1 in waves and current and validation against model test measurements

With the continuous growing of the aquaculture industry and increasingly limited fish farming sites at close to shore areas both in Norway and worldwide, there is a need to develop fish farms suitable for aquaculture production in typical offshore environments. For this purpose, SALMAR has developed and deployed the Ocean Farm 1 facility for offshore fish farming.The main purpose of this paper is to develop a reliable numerical model and investigate the motion responses of the Ocean Farm 1 structure in waves and current. The established numerical model consists of the Ocean Farm 1's frame structure (with rigidly-connected circular column components), the net and the mooring system. The hydrodynamic external loads and coefficients of the frame structure are obtained by using potential flow theory. The quadratic drag load on the individual circular columns of the frame structure is formulated by a given drag coefficient. The loads on the net are formulated by using the screen model, where the Reynold number dependent lift and drag forces are formulated as a function of the solidity ratio Sn of the net, relative inflow angle and velocity. The hydrodynamic loads on the mooring lines are formulated using the Morison's equation and the structural responses of the mooring lines are obtained using a nonlinear FE model.With the developed numerical model, time domain simulations are performed. The simulation results are firstly validated against measured data from the decay tests, current tests, and regular wave tests. After the validation, numerical simulations are performed in different irregular wave and current combined weather conditions and the obtained motion response of Ocean Farm 1 are discussed and compared with available measurement data.     

不规则波和流下的重力式网箱水弹性响应研究

文章对重力式网箱在不规则波和流作用下的水弹性响应分析进行了研究,通过有限元方法建立实尺度网箱模型并对网箱的运动和变形进行了分析。在数值模型中,通过非线性弹簧单元和Truss单元来模拟锚链和渔网结构,通过若干耦合的梁按照"浮力分配法"来计算浮圈的瞬时浮力。基于这个计算模型,文中充分研究了当网箱处于波流载荷下,浮圈的各阶弹性体模态所占权重。结果显示,当有义波高增大时,在垂直方向上会激发出更多的浮圈弹性体模态,而流则主要影响水平方向上的刚体模态。     

波浪作用下单体网格式浮架受力的数值模拟

模型试验表明重力式网箱在波浪作用下，单纯浮架的受力贡献比例较大。本文运用波浪理论，通过建立浮架、锚绳及浮子的运动方程，采用五阶龙格-库塔进行数值求解，得到了单体网格式锚碇单纯浮架的数值计算模式。将计算模型简化为四点锚碇，并将计算结果与实验结果进行了比较，二者符合程度较好。在此基础上，比较了单体网格式锚碇与四点锚碇单纯浮架的受力，结果表明网格式锚碇方式浮架受力较小。     

一种舰船推力测量装置的结构和电磁兼容性设计

设计了一种利用推力传感器测量舰船推力轴承块的压力进而计算出螺旋桨推力的装置.其设计包括系统结构设计和系统电磁兼容性设计.系统整体结构包括推力传感器（感测推力大小,转换成电信号;其中4只测量正车推力,2只测量倒车推力）、传感器级联箱（信号传输及偏载误差调整）和推力显示仪（数据采集和显示）.系统采用整体电磁兼容性设计,抗干扰能力强、可靠性高.推力传感器采用轮辐式结构,突破了薄式小体积、高精度、大量程高过载、耐潮湿及长寿命等关键技术.推力显示仪针对舰船实际情况,实现了数据采集和实时监测功能,数据采集精度达0.2%等级.系统通过了船用环境试验及电磁兼容性试验,且裕量明显,能够安全、稳定、可靠地运行于舰船上.     

船舶结构分布式测量系统及其模型

基于船舶挠性结构变形测量的现状、捷联惯导系统的应用现状和目前光纤布拉格传感器可复合使用、波长编码的独特优点,本文提出采用捷联惯导系统与分布式光纤布拉格光栅组成对船舶结构进行变形测量和健康监测的设计方案,分析了可行性,并建立了由捷联惯性系统和光纤布拉格传感器组成的光电多传感器初步测量模型.     

光纤Bragg光栅传感器在智能船舶结构中的应用

光纤光栅传感器除具有一般普通光纤传感器体积小、灵敏度高、带宽宽、抗电磁干扰能力强和耐腐蚀外,还具有易集成、本征自相干性好、波长编码、可实现实时测量和分布式测量等独特优点,近年已成为新型传感及国际智能结构领域中的研究热点.文章介绍了光纤Bragg光栅传感器的基本原理,综述了其在国外船舶结构中的应用,分析了光纤Bragg光栅传感器在信息化智能舰船中能起到的作用和在智能船舶结构中应用的关键技术.     

浅谈系泊设备安装拉线定位工艺

为保证船舶系泊设备的安装、调试过程中做到有序合理,施工精度需符合图纸及相关船东、船级社的要求,使用性能符合船级社及ISO标准要求。根据南通象屿海洋装备有限责任公司实际执行情况,并结合系泊设备实际操作使用惯例,阐述了系泊设备安装拉线定位工艺的主要工艺技术要求及施工注意要点。     

FBG应变传感器在隧道长期健康监测中的应用

隧道结构长期运营安全监测需要采用长效性好的传感测试技术，近年发展起来的光纤光栅传感器是一种数字式的光纤传感技术，具有长期稳定性好、测量精度高和适宜远程监测等优点。将光纤光栅传感器应用于厦门翔安隧道结构健康监测系统，实现了对二次衬砌混凝土应变的长期监测。结果表明光纤光栅传感器测量数据稳定可靠，监测效果良好。     

建造中的船体在船台上的应力松驰现象研究

为得到建造中的船体在船台上的船体变形数据,基于FBG技术设计了船体在船台上的蠕变和应力松驰现象的监测系统,将该系统布置在实际船体结构上,测量了在船台上受结构蠕变和结构应力松驰现象综合作用所造成的船体结构变形,分析了监测过程中造成船体结构变形的因素,指出应力松驰是主要因素。数据分析表明:利用FBG传感技术进行船体变形长期监测是可行的;船体在船台上存在结构蠕变和应力松驰现象。最后,并基于壳体理论估算了船台上的船体结构的内应力释放速率。     

高速双体穿浪船艏部结构动态位移监测与分析

为了测量穿浪双体船艏部结构在航行过程中的动态变形,并分析其变形的规律,文章利用光学微动测量系统对船体艏部结构的变形进行实时监测,并对测量数据进行实时自动采集与存储。试验结果表明:航行过程中动态变形为4.72 mm~7.60 mm;低海况高航速下的结构变形明显大于高海况低航速下的结构变形;在不同航向试验中,顶浪航行结构变形最大,艉斜浪、艏斜浪和顺浪工况相差不大。分析结果既可论证微动测量法监测动态变形的可行性,又可为高速双体穿浪船艏部结构疲劳裂纹和变形等机理研究及局部优化提供参考。     

基于双总线的机舱温度监测报警系统设计

针对机舱中需要进行温度监测的设备和系统,将一线总线技术与CAN现场总线技术有机结合,采用DS18B20数字式温度传感器设计机舱温度监测报警系统,并可作为机舱监测报警系统中的一个信号采集单元（SAU）,增强了温度监测的准确性、实时性。     

大潮差条件下浮式防波堤锚泊线组合形式的试验研究*

通过物理模型试验研究了在大潮差条件下不同锚泊线组合形式对浮箱式防波堤运动响应和锚链拉力特性的影 响。其中,锚泊系统布置形式采用平行型,组合形式有链+重块、链+重链、链+钢丝绳和链+尼龙绳4种。探讨了不同组合 形式的锚泊系统在大潮差条件下的优劣,给出一种比较适合大潮差的锚泊线组合形式,为实际工程提供参考。     

舰船动力系统数字孪生技术体系研究

[目的]为了实现数字孪生技术在舰船动力系统中的应用,针对舰船动力系统集成度高、全寿期研制特点,梳理在动力系统研制中应用数字孪生技术的技术路线。[方法]利用数字孪生技术的虚实融合与实时交互、迭代运行与优化、全要素与全流程数据驱动等优势,开展符合动力系统研制特点的数字孪生技术体系研究。[结果]经研究,构建了舰船动力系统中应用数字孪生的技术体系,包括规范、平台构建、关键技术、数字孪生体建设、集成验证与示范应用。[结论]研究成果可为舰船动力系统数字孪生技术示范应用及实践提供参考。     

40万吨级超大型油轮船舶系泊动态响应的试验研究

为探讨超大型油轮在现有码头停靠、作业时的系泊情况,采用船舶系泊物理模型试验方法,分析研究了40万吨级油轮系泊作业时在长周期波及波浪、风、流联合作用下,系泊船舶的动态响应及对系缆力、护舷撞击力的影响。得出了40万吨级油轮在系泊作业过程中在不同波高及周期的波浪作用下运动量、缆力、撞击力的变化规律,提出在试验条件下40万吨级油轮停靠码头系泊作业的系缆方式及应注意问题。可为40万吨级油轮系泊作业提供依据。     

Hinge joint damage identification method of soft yoke mooring system based on multibody dynamic modeling and structural monitoring data

Soft yoke mooring system (SYMs) is a single-point mooring system used in shallow water oil and gas development. In general, SYMs consists of mooring framework support, mooring legs, yoke, and single-point turret and it forms a multibody dynamic system with 13 hinge joint structures such as universal joints and thrust bearings. The hinge joint is one of the key components of SYMs; therefore, it is necessary to accurately evaluate the operating behavior of the hinge joints. In this study, real-time damage identification is conducted based on the multibody dynamic features of the SYMs. First, a long-term monitoring strategy for the prototype application is developed based on the multibody governing equations of the SYMs. The motion behaviors and stress state of the hinge joints and bodies are calculated using prototype monitoring data. A hinge joint damage identification based on the virtual moment is proposed by considering the changes in the friction coefficient in the damage state. The virtual moment method is used to transform the damage identification problem of the SYMs into a problem of seeking the optimal solution to the dynamics identification function. Genetic algorithm (GA) is implemented to seek the optimal solution of the friction coefficient of each hinge joint. A large-scale model testing system of the SYMs is established to perform the damage identification of the bottom hinge joints of the SYMs. The results show that the proposed method can effectively identify the damage degree and position of the hinge joints of the SYMs and provide a real-time warning system for the in-service operation of the SYMs.     

一种基于互素阵的孔径扩展方法

物理阵元数一定的情况下,通过孔径扩展虚拟出大孔径的方法可以提高目标方向估计的分辨率。本文提出使用基于互素阵的孔径扩展方法,该方法基于互素定理,通过满足一定规则的非均匀布阵,使用两物理存在阵元接收到的信号虚拟出一新的阵元,如此将此非均匀阵列扩展为孔径较大的均匀线阵,然后进行目标波达方向估计。仿真和水池试验表明该孔径扩展方法可以显著地提高空间分辨率,以及能够得到更低的旁瓣级,显然能节省物理阵元,对工程应用来说能降低成本,所以具有良好的应用前景。     

基于数字孪生的舰船蒸汽动力总体模型框架研究

[目的]为了实现舰船蒸汽动力系统的数字化、网络化和智能化,提出一种总体数字孪生模型应用体系。[方法]从物理对象、过程要素、生命周期及虚拟空间这4个维度,提出基于数字孪生的舰船蒸汽动力系统总体“四维思想模型”,并创建总体全生命周期的“五阶体系模型”,涵盖概念论证、系统设计、总装建造、试验试航及运维保障这5个典型的阶段。通过引入大数据、物联网、云计算、人工智能和基于模型的系统工程等先进技术,形成由物理层、接口层、数据层、模型层、调度层、功能层及应用层组成的舰船蒸汽动力系统总体数字孪生“7层架构模型”。[结果]舰船蒸汽动力系统虚拟设计分析及试验平台的验证结果表明,数字孪生体系框架可以有效支撑系统方案设计、操作运行分析及试验方案评估,从而实现舰船全生命周期中物理空间与虚拟空间的交互协同。[结论]研究成果可为舰船蒸汽动力系统的总体数字化设计提供参考。