船舶撞击对码头结构耐久性影响分析

介绍、分析当前研究船舶撞击码头问题的各种方法的优劣势。从理论的角度分析、总结船舶撞击对码头结构的损伤及耐久性的影响机理,并通过整理各地码头耐久性的现状,提出评估和修复办法。     

船舶失控撞击高桩码头结构的数值仿真分析

以5万吨级散货船在失控状态下以1 ms的速度垂直撞击某高桩码头为例,运用有限元软件模拟该撞击的过程,得到对应撞击的能量转化情况以及船舶撞击作用力的时程曲线,并将撞击力仿真计算结果与各类船桥碰撞规范撞击力计算结果进行比较。同时,通过对撞击后码头结构破坏情况进行分析,提出防止码头结构由于船舶失控撞击而破坏的措施,为同类码头的设计、维护及改造提供理论依据。     

基于监测的宽窄抗冰锥体结构判据分析（英文）

Ice-induced structural vibration generally decreases with an increase in structural width at the waterline. Definitions of wide/narrow ice-resistant conical structures, according to ice-induced vibration, are directly related to structure width, sea ice parameters, and clearing modes of broken ice. This paper proposes three clearing modes for broken ice acting on conical structures: complete clearing, temporary ice pile up, and ice pile up. In this paper, sea ice clearing modes and the formation requirements of dynamic ice force are analyzed to explore criteria determining wide/narrow ice-resistant conical structures. According to the direct measurement data of typical prototype structures, quantitative criteria of the ratio of a cone width at waterline(D) to sea ice thickness(h) is proposed. If the ratio is less than 30(narrow conical structure), broken ice is completely cleared and a dynamic ice force is produced; however, if the ratio is larger than 50(wide conical structure), the front stacking of broken ice or dynamic ice force will not occur.     

超级游艇舒适度评估的振动分析（英文）

Comfort levels on modern superyachts have recently been the object of specific attention of the most important Classification Societies, which issued new rules and regulations for evaluating noise and vibration maximum levels. These rules are named Comfort Class Rules and set the general criteria for noise and vibration measurements in different vessels' areas, as well as the maximum noise and vibration limit values. As far as the vibration assessment is concerned, the Comfort Class Rules follow either the ISO 6954:1984 standard or the ISO 6954:2000. After an introduction to these relevant standards, the authors herein present a procedure developed to predict the vibration levels on ships. This procedure builds on finite element linear dynamic analysis and is applied to predict the vibration levels on a 60 m superyacht considered as a case study. The results of the numerical simulations are then benchmarked against experimental data acquired during the sea trial of the vessel. This analysis also allows the authors to evaluate the global damping ratio to be used by designers in the vibration analysis of superyachts.     

对一型潜器的水下振动响应分析（英文）

文章基于三维水弹性方法,分析了一型潜水器水下航行中的振动响应特性,通过求解干模态的广义坐标响应及对应的附连水质量,确定了干模态频率和湿谐振频率的对应关系。该文预报的水下响应曲线的峰值频率得到了水声试验测试结果的印证,说明了三维水弹性方法在求解水下结构振动响应问题上的有效性。文中最后对潜器尾部结构进行了改进,改进前后速度响应幅值曲线的比对表明,增加尾部纵桁结构的刚度对抑制潜器的尾部振动有明显的效果。     

腐蚀对双壳超大型原油运输船船体的影响研究（英文）

This study aims to examine and analyze the effect of corrosion wastage on the ship hull of a double hull very large crude oil carrier. To calculate the ultimate bending moment capacity, along with the neutral axis position at the limit state, section modulus, and moment of inertia, the incremental-iterative method is employed. This paper also considered the residual strength checking criteria of ship hull and the ultimate stress behaviors of the representative structural elements. Then, Paik's probabilistic corrosion, which employs two levels of corrosion rate and three different assumptions of coating life time, is applied to assess the corrosion effects. The calculation results obtained through relevant analyses are also presented.     

用于浅水环境大型藻类监测的新型海底着陆器（英文）

The colonization of underwater environments by exotic seaweeds is causing major ecological problems around the world. This project, referred to AMALIA, aims to transform this current ocean threat into an opportunity by adding value to the macroalgae present off the northwest of the Iberian Peninsula. To do so and to observe the presence of seaweeds in situ, an ocean modular submersible platform was developed. This platform was designed to be capable of detecting and surveying surges of invasive seaweeds while withstanding sea conditions. Conceptual designs followed by a screening process were performed, taking into consideration criteria such as operational range and modularity. An open-frame lander was considered and further developed using buckling criteria. In parallel, a state-of-the-art monitoring system was created using spectral imaging, allowing for the future creation of a macroalgae identification system. In addition, sensorial systems for characterizing growth conditions were introduced. Laboratory trials were executed to assess the capability of the system, and sea trials are currently being performed.Numerical simulations and laboratory trials indicate that the structure is fully capable of being deployed for shallow-water environments with a state-of-the-art invasive seaweed monitoring system while maintaining a high degree of modularity.     

波浪中船底空泡对振动吸收的研究（英文）

Bottom ventilated cavitation is the successfully proven ship drag reduction technology, but the impact of sea waves on ships with bottom cavities is the substantial concern for a broad technology implementation. The influence of waves on vertical force experienced by such ships is analyzed in this paper using a perturbation technique. The unperturbed cavity shape at given Froude number and cavity length was found from a nonlinear steady ideal fluid problem. The ship response to an impact of a wave of the given length and amplitude is considered as the one-frequency perturbation. This perturbation was found by combined consideration of compressible flow in the cavity and incompressible flow in the surrounding water. Computational examples relate to an earlier tested model with the bottom cavity restricted by skegs. The vertical forces on the model with bottom cavities and in cavitation-free conditions were compared in head and following seas. It was found that within the major part of the consider range of wavelengths the cavity acts as a shock absorber significantly reducing the vertical force pulsation and ship acceleration in waves.     

浸没式穿孔板对超大型浮体的水弹性响应影响（英文）

Scattering of oblique flexural-gravity waves by a submerged porous plate in a finite water depth is investigated under the assumptions of linearized surface waves and small-amplitude structural response. The study is carried out using eigenfunction expansions and the corresponding orthogonal mode-coupling relations associated with flexural-gravity waves in uniform water depth. The characteristics of the roots of the complex dispersion relation are examined using the principle of counting argument and contour plot. Characteristics of the flexural-gravity waves are studied by assuming both the floating elastic plate and the submerged porous plate are infinitely extended in horizontal directions. The effectiveness of the submerged porous structure on the reflection, transmission, and dissipation coefficients is analyzed for various wave and structural parameters.     

一个在船舶推力分配中避免奇异结构的简单方法（英文）

处在奇异结构的船舶可能会突然失位,因为无法及时提供船舶所需的推力。文章提出了一个在船舶推力分配中避免奇异结构的简单方法。为了验证这个简单方法的效果,进行了一个半潜平台的时域模拟。时域模拟中用到了两种避免奇异结构的方法,包括新提出的方法和文献中经常提到的典型方法。从结果中可以得出,这个新方法具有和典型方法同样好的推力分配效果。用这个简单方法,虽然消耗的能量有少量增加,但时域模拟所花的时间大大地缩减了。这个简单方法的高效率可以保证它在船舶动力定位的实时推力分配中得到更广的应用。     

双层底船搁浅场景下结构响应的快速预报（英文）

This study presents a simplified analytical model for predicting the structural responses of double-bottom ships in a shoal grounding scenario. This solution is based on a series of analytical models developed from elastic-plastic mechanism theories for different structural components, including bottom girders, floors, bottom plating, and attached stiffeners. We verify this simplified analytical model by numerical simulation, and establish finite element models for a typical tanker hold and a rigid indenter representing seabed obstacles. Employing the LS-DYNA finite element solver, we conduct numerical simulations for shoal-grounding cases with a wide range of slope angles and indentation depths. In comparison with numerical simulations, we verify the proposed simplified analytical model with respect to the total energy dissipation and the horizontal grounding resistance. We also investigate the interaction effect of deformation patterns between bottom structure components. Our results show that the total energy dissipation and resistances predicted by the analytical model agree well with those from numerical simulations.     

基于磁流变弹性体的船舶轴系纵振动力吸振器的实验研究（英文）

磁流变弹性体是一种新型的智能材料,由微米级的羰基铁粉和聚合物合成。由于它具有弹性模量可调、无需封装、稳定性好、响应快等优点,已被广泛应用于机械振动控制等领域。文中针对船舶推进轴系纵振动力学特性,提出一种固有频率可调的磁流变弹性体动力吸振器用于轴系纵振控制。首先理论分析了安装动力吸振器的推进轴系的动力学模型,其次对动力吸振器进行了移频特性试验,并在1:4的船舶轴系缩比模型上进行了变转速工况下吸振效果试验。实验结果表明,该吸振器具有12.3 Hz的移频范围,并且在不同轴系工作转速下相比于被动式吸振器均有更好的吸振效果。     

四柱结构近场干涉的粘流分析（英文）

The hydrodynamic analysis of multi-floating bodies is important and widely used in marine engineering. In this study, we systematically simulated the wave diffraction problem of a fixed vertical four-cylinder structure in regular waves in the time domain in a viscous numerical wave tank. The hydrodynamic interaction of waves with a bottom-mounted structure consisting of four vertical cylinders arranged at the corners of a square shows a complicated interference phenomenon. In this paper, we illustrate and analyze the run-up around the structure and the corresponding wave forces. To investigate the viscous effect on the near-trapping phenomenon, we pay particular attention to investigating the waves near-trapped inside the four-cylinder structure,and make a comparative study of the viscous-and inviscid-flow solutions with the experimental measurements. The results show that the maximum wave elevation occurs on the inner side of the leeside cylinder, and that the wave elevations on the outer side of the cylinders are lower than those on the inner side. We can conclude that viscosity has an obvious damping effect on wave elevations inside the structure. The cylinders show a tendency to drift apart from each other when the near-trapping phenomenon occurs.     

环向加肋对充液圆柱壳振动特性的影响分析（英文）

文章研究了环向加肋对充液圆柱壳耦合振动的影响。基于Love壳体理论,考虑壳体内部完全充液,采用波动法建立充液环肋圆柱壳耦合振动的频率特征方程,得到了不同边界条件下的耦合频率值。通过与已有文献数据对比,验证了文中研究方法的有效性和正确性。最后通过算例,分析了环肋参数对充液圆柱壳结构耦合振动的影响。结果表明,肋骨尺寸、数目的增加,对充液圆柱壳振动频率的提升影响明显,而内、外加肋形式所产生的影响则相对有限;肋骨对频率的影响主要表现在周向波数较大时;肋骨高度变化对耦合振动频率的影响更明显。     

具有化学废热回收功能的船舶推进系统效率分析（英文）

One of the basic ways to reduce polluting emissions of ship power plants is application of innovative devices for on-board energy generation by means of secondary energy resources. The combined gas turbine and diesel engine plant with thermochemical recuperation of the heat of secondary energy resources has been considered. It is suggested to conduct the study with the help of mathematical modeling methods. The model takes into account basic physical correlations, material and thermal balances, phase equilibrium, and heat and mass transfer processes. The paper provides the results of mathematical modeling of the processes in a gas turbine and diesel engine power plant with thermochemical recuperation of the gas turbine exhaust gas heat by converting a hydrocarbon fuel. In such a plant, it is possible to reduce the specific fuel consumption of the diesel engine by 20%. The waste heat potential in a gas turbine can provide efficient hydrocarbon fuel conversion at the ratio of powers of the diesel and gas turbine engines being up to 6. When the diesel engine and gas turbine operate simultaneously with the use of the LNG vapor conversion products, the efficiency coefficient of the plant increases by 4%–5%.     

采用非概率方法对不同环境条件下的漂浮式风力机进行系泊损伤识别（英文）

This paper discusses the damage identification in the mooring line system of a floating wind turbine(FWT) exposed to various environmental loads. The proposed method incorporates a non-probabilistic method into artificial neural networks(ANNs). The non-probabilistic method is used to overcome the problem of uncertainties. For this purpose, the interval analysis method is used to calculate the lower and upper bounds of ANNs input data. This data contains some of the natural frequencies utilized to train two different ANNs and predict the output data which is the interval bounds of mooring line stiffness. Additionally, in order to reduce computational time and more importantly, identify damage in various conditions, the proposed method is trained using constant loads(CL) case(deterministic loads, including constant wind speed and airy wave model) and is tested using random loads(RL) case(including Kaimal wind model and JONSWAP wave theory). The superiority of this method is assessed by applying the deterministic method for damage identification. The results demonstrate that the proposed non-probabilistic method identifies the location and severity of damage more accurately compared to a deterministic one. This superiority is getting more remarkable as the difference in uncertainty levels between training and testing data is increasing.     

基于波分析法油膜刚度对轴系扭转振动影响的研究（英文）

为确保带减速齿轮箱主推进系统的可靠性,文章对船舶轴系的扭转振动进行了研究。首先根据各组成部件的特点将轴系分解为连续和离散的两个子系统,分别利用波分析法和多自由度系统分析法列出连续子系统的波动形式及离散子系统的振动微分方程,同时考虑了减速齿轮箱油膜刚度的影响。然后根据两子系统连接处的动态平衡和连续条件,建立整个轴系在扭转振动模式下总运动方程,通过求解总方程得到系统的位移响应。该扭转振动分析被应用到某LNG船带减速齿轮箱的轴系振动计算中,通过考虑轴系减速齿轮箱啮合齿面间油膜刚度使轴系扭转振动模型更接近轴系实际运转工况。计算结果显示:随着减速齿轮箱啮合齿面间油膜刚度的增加,最大轴系扭转应力向低转速区域偏移。这对船舶轴系转速禁区的划分产生极大的影响。有助于防止因不良轴系振动计算引起轴系事故的发生。     

采用自动识别系统对水下输气管线、离岸平台和船舶检验评分的实时监测（英文）

The aim of this research is to develop an algorithm and application that can perform real-time monitoring of the safety operation of offshore platforms and subsea gas pipelines as well as determine the need for ship inspection using data obtained from automatic identification system(AIS). The research also focuses on the integration of shipping database,AIS data, and others to develop a prototype for designing a real-time monitoring system of offshore platforms and pipelines. A simple concept is used in the development of this prototype, which is achieved by using an overlaying map that outlines the coordinates of the offshore platform and subsea gas pipeline with the ship's coordinates(longitude/latitude) as detected by AIS. Using such information, we can then build an early warning system(EWS) relayed through short message service(SMS), email, or other means when the ship enters the restricted and exclusion zone of platforms and pipelines. The ship inspection system is developed by combining several attributes. Then, decision analysis software is employed to prioritize the vessel's four attributes, including ship age, ship type, classification, and flag state.Results show that the EWS can increase the safety level of offshore platforms and pipelines, as well as the efficient use of patrol boats in monitoring the safety of the facilities. Meanwhile, ship inspection enables the port to prioritize the ship to be inspected in accordance with the priority ranking inspection score.