Forecasting Baltic Dirty Tanker Index by Applying Wavelet Neural Networks

Baltic Exchange Dirty Tanker Index (BDTI) is an important assessment index in world dirty tanker shipping industry. Actors in the industry sector can gain numerous benefits from accurate forecasting of the BDTI. However, limitations exist in traditional stochastic and econometric explanation modeling techniques used in freight rate forecasting. At the same time research in shipping index forecasting e.g. BDTI applying artificial intelligent techniques is scarce. This analyses the possibilities to forecast the BDTI by applying Wavelet Neural Networks (WNN). Firstly, the characteristics of traditional and artificial intelligent forecasting techniques are discussed and rationales for choosing WNN are explained. Secondly, the components and features of BDTI will be explicated. After that, the authors delve the determinants and influencing factors behind fluctuations of the BDTI in order to set inputs for WNN forecasting model. The paper examines non-linearity and non-stationary features of the BDTI and elaborates WNN model building procedures. Finally, the comparison of forecasting performance between WNN and ARIMA time series models show that WNN has better forecasting accuracy than traditionally used modeling techniques.

Analysis on Motion and Cable Dynamic Tension for An ALT-Tanker System

A two-degree freedom model for an ALT-tanker system is established corresponding to the pitch of the ALT and the surge of the tanker.Tension in the mooring cable between the ALT and the tanker is represented by an unsymmetrical,piecewise-nonlinear function.Wave load on the tower is evaluated by use of the Morison equation.The first order wave load acting on the tanker is calculated by the linear diffraction theory based on the 2-D Helmholtz equation,and the near field approach of Pinkster is used to evaluate the second order drift force.The dynamic equation of motion is established based on the principle of D＇lembert.Dynamic response and cable tension of a mooring system composed of an 88.4 m ALT and a 100000 t grade tanker are calculated.The influence of wave frequency,wave excitation amplitude,wind and current force on ALT-tanker motion and cable tension is discussed.

Comparison analysis between CSR-OT and CSR-H for corrugated bulkhead of large product tankers

Large Aframax product tanker(more than 100k DWT),with centerline longitudinal corrugated bulkheads and transverse corrugated bulkheads in cargo area,is the largest type of product tanker at present.The external draft of Harmonized Common Structural Rules(CSR-H)for Bulk Carriers and Oil Tankers is released for external review.More attentions are paid to the impact of CSR-H on the structural design of the corrugated bulkhead of large Aframax product tankers.Based on CSR-OT and CSR-H,it discusses the impact of CSR-H on the corrugated bulkhead by strength assessment of a 115k DWT product tanker.

Strength Analysis of Turret Mooring Productive/Storage Tanker

The longitudinal strength of turret mooring productive/storage tanker is studied. A numerical example has been implemented according to the method presented in this paper to give practical illustration. From the results of the numerical example, it is concluded that the turret hole located near the forward of the amidships has small effect on the longitudinal strength of the ship hull. As for design extreme value of wave bending moment of storage tanker, statistic method is a more reasonable methodology, especially with the consideration of the servere environmental conditions. The primary estimation of design section modulus of turret storage tanker can be determined by this design bending moment.

Horizontal Slow Oscillation of a Moored Tanker and Numerical Method of Hopf-Bifurcation

In this paper, a six-order nonlinear dynamic model with three degrees of freedom is presented for the study of the 'fishtail' motion of a Single Point Mooring System. The effect of parameter variations on the equilibrium state of the system is analyzed. In order to study the stability of the equilibrium state, the mooring-line length l is chosen as a bifurcation parameter, so that all eigenvalues of the Jacobian matrix under different parameters can be worked out, and then the Hopf-bifurcation point can be found. Finally, the Hopf-bifurcation periodic solution of the system is computed.

Dynamic Analysis of a Turret-Moored Tanker

In this paper, the second-order perturbation method in frequency domain is used to calculate RAO and spectra of motion and mooring line tension of a turret-moored tanker in ballast condition. The calculated results are compared with corresponding experiment results. In the experiment the wave heading is 180 degrees, and the wave spectra is the P-M spectrum and white noise spectrum. In the theoretical calculations, the damping coefficient of slow oscillation of the tanker is determined on the basis of the damping obtained from a test of irregular waves where the mooring system is replaced by a nonlinear spring with nonlinear stiffness similar to that of the mooring system. From the comparison between theoretical calculations and experiment al results, it can be found that the theoretical results obtained by the second-order perturbation method in frequency domain are in good agreement with the experimental results, indicating that the damping coefficient of slow oscillation of the tanker required in frequency domain calculation can be determined by reference to the damping coefficient of the tanker moored by a spring system in irregular waves, and the second-order perturbation method can be used to analyze the dynamic response of a turret-moored tanker.

Experimental Study on Allowable Berthing and Mooring Conditions of An Oil Tanker

When an oil tanker under the combined action of wind, waves and tidal current and is berthed or moored to a platform, the impact forces on the fenders and the tensile force in the mooring lines are important factors in the studies of berthing and mooring conditions. Based on the experiment of a berthing and mooring tanker model under the action of wind, wave and tidal current in the same direction, this paper studies the allowable berthing and mooring conditions by considering the tensile forces of mooring lines and impact forces on the fenders, as well as the impact energy on the fenders. And a method has been proposed here for motion amplitude analysis. A successful method to decrease impact forces on the fenders is put forward. Blowing in wind and blowing off wind and different angles between waves and the fenders are considered in the experimental study. In the berthing tests of the tanker model, the impact forces are measured and the impact energy is calculated, then the berthing conditions are determined. In the mooring tests of the tanker model, the mooring line tensile forces and impact forces are measured, and the allowable mooring conditions are given that will be useful to engineering design.

Uncertainty Modeling for Oil Tankers and Operational Guidance

Technology evolution has been a driving factor in the oil tanker industry. The technology breakthroughs and historical data served as the main factor of evo-lution in the industry. Nowadays the oil tankers have been modified and opti-mized according to the requirements of the cargo and the area in which they are supposed to operate. This paper reviews some technological developments in the tanker industry and driving factors behind them. The issues of environmental pollution, failure prediction, and efficient operations are also discussed in mathematical terms.

Safety Indications of Navigation Audit for Tankers to Develop a Bridge Inspection Method

A significant amount of world trade has been carried out by maritime transportation. In 2016, world maritime trade volume increased by 2% and reached 10.3 billion tons, 55,057 global ton-miles. There has been a significant increase in quantity and tonnage of tankers, with the requirement for well qualified and experienced personnel in the maritime industry. Therefore, employment has become a serious problem. Major Oil Companies (MOCs), port states, classification societies, and flag states have increased the number of inspections on tankers due to safety concerns. Tanker inspections are becoming more difficult and inefficient due to intensive cargo operations. Inefficient, subjective or substandard inspections/evaluations are usually leading to incorrect decisions, and causing an unfair market. In addition, corrective actions cannot be carried out properly, and decision making authorities cannot give the best decisions about vessels and their operator companies due to lack of scientific methods. In this study, details are identified such as finding the root causes, identifying the risks, understanding the possible consequences, and determining the working areas during the ship crews’, operators’, auditors’ and charterers’ working and ship selection periods. Pairwise comparisons were carried out by means of surveys on ship masters (captains), chief officers, deck officers, and superintendents. Five criteria—Crew, Equipment, Company, Structure, and ISM (International Safety Management) were weighted using Analytical Hierarchy Process (AHP). Finally, Bridge Safety Support System (BSSS) was developed according to criteria weights. In this way, best choices can be offered to ship charterers about which ship is better for a company’s interests. And, carrying out bridge inspections and corrective actions will be more reliable and effective for maritime transportation. Statistical data and vessel improvements will be obtained in BSSS. As a result, fair market conditions will be available in maritime industry with the help of this study.

Omni Tanker:代表澳洲制造走向世界

2007年首推碳复合材料罐体概念在传统的观念里,专用汽车产品的进步应该是循序渐进一步一个脚印的。但是一个产品爆发性的进步会打破和挑战原有的市场平衡基础。2007年,一家位于澳大利亚悉尼的年轻的罐式车生产新军推出了一款名叫＂Evolution Tanker＂（进化罐车）的产品,带来了世界上第一款使用碳复合材料的罐体,用于散装液体化学品领域。

A New Arrangement with Nonlinear Sidewalls for Tanker Ship Storage Panels

Sloshing phenomenon in a moving container is a complicated free surface flow problem. It has a wide range of engineering applications, especially in tanker ships and Liquefied Natural Gas (LNG) carriers. When the tank in these vehicles is partially filled, it is essential to be able to evaluate the fluid dynamic loads on tank perimeter. Different geometric shapes such as rectangular, cylindrical, elliptical, spherical and circular conical have been suggested for ship storage tanks by previous researchers. In this paper a numerical model is developed based on incompressible and inviscid fluid motion for the liquid sloshing phenomenon. The coupled BEM-FEM is used to solve the governing equations and nonlinear free surface boundary conditions. The results are validated for rectangular container using data obtained for a horizontal periodic sway motion. Using the results of this model a new arrangement of trapezoidal shapes with quadratic sidewalls is suggested for tanker ship storage panels. The suggested geometric shape not only has a maximum surrounded tank volume to the constant available volume, but also reduces the sloshing effects more efficiently than the existing geometric shapes.

3-D computational method of wave loads on turret moored FPSO tankers

A three-dimensional method of calculating wave loads of turret moored FPSO (Flo ating Production Storage and Offloading) tankers is presented. The linearized restoring forces acting on the ship hull by the mooring system are calculated according to the catenary theory, which are expressed as the function of linear stiffness coefficients and the displacements of the upper ends of mooring chains. The hydrodynamic coefficients of the ship are calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for ships with a low forward speed. The equations of ship motions are established with the effect of the restoring forces from the mooring system included as linear stiffness coefficients. The equations of motions are solved in frequency domain, and the responses of wave-induced motions and loads on the ship can be obtained. A computer pro gram based on this method has been developed,and some calculation examples are illustrated. Analysis results show that the method can give satisfying prediction of wave loads.

Ultimate Strength Assessment of a Tanker Hull Based on Experimentally Developed Master Curves

几何上类似的可伸缩由制造了的 A 到照原尺寸的使硬的面板然后他们的倒塌行为的小规模的标本被调查。这被考虑使硬的面板压缩最终的力量测试根据几何可伸缩的法律被设计以便测试的输出能受到垂直弯曲的油轮壳的压缩地区的使硬的面板被用作代表性时刻。油轮壳的最终的力量被 FE 分析用被横梁紧张测试和使硬的面板的压缩测试获得的试验性地发达的主人压力紧张曲线分析，并且当时与进步倒塌方法完成的结果相比。

Accidents during Tanker Accident in Confined Spaces

当工作机载的油轮在限制空格正在工作时，专业之一冒险，改进在在如此的空格工作的过程是明显的，但是开发在营救操作使用的设备是稀罕的发生，那是这份报纸正在集中于在手册之间区分的原因与更多的发达设备在 rescuing 特殊使用在如此的一足够的时间的全体乘务员，救工人命。用手的方法被称为被用于营救目的泥泞的鹤在任何限制空格，机载的油轮应该被代替由胜过是空气或水力的驾驶机器的鹤，完成更好的结果。作为安全措施，在如此的任务采取的措施不是为要求的客观成就的足够。如此的安全过程被讨论了，批评状况被指出了。

穿梭油轮新型卧式艏装载系统设计研究

穿梭油轮在现代海洋原油运输中扮演着重要角色,艏装载系统是其核心组成部分之一,在原油串靠外输过程中至关重要。目前,我国海洋原油外输作业多采用船舯软管外输方式,与艏装载系统的船艏输送相比,存在一些局限性。针对南海东部地区船舶使用原油外输艏装载技术所面临的问题,从介绍艏装载系统船艏输送的作业流程出发,通过与国外传统穿梭油轮的艏装载方式相比,提出一种新型卧式艏装载系统布局方案,优化艏装载系统的结构,为穿梭油轮艏装载改造设计提供参考。

常压罐车罐体检验机构资质管理与技术要求研究

我国常压罐车罐体的第三方检验分为出厂检验和定期检验,常压罐车罐体检验机构管理和检验技术要求存在较多问题。通过分析我国常压罐车罐体检验机构资质要求和技术要求,提出了相应的对策建议,可为常压罐车罐体的生产、检验、认可、监管提供参考。

基于多项Logistic的危化品槽罐车火灾类型判别

为有效防控危化品槽罐车火灾事故,准确判别槽罐车火灾类型,运用Python统计我国2013—2020年危化品槽罐车道路火灾案例;在确定火灾事故特征的基础上,将3种危化品槽罐车火灾类型(喷射火灾、池火灾与沸腾液体膨胀蒸气爆炸火灾(BLEVE))作为被解释变量类别,确定空间与道路特征、时间与气象特征、人员因素、车辆及设备因素以及危化品因素5个方面共15项火灾因子;构建基于多项Logistic危化品槽罐车火灾类型判别模型;开展准确性检验和显著性检验以及实例应用,获得3种火灾类型的发生概率,并提出相应的火灾防治措施。结果表明:实例中液化天然气(LNG)罐车最有可能发生池火灾,其概率为0.55;其次为喷射火灾,BLEVE火灾的概率最小。采取提高危化品容器机械强度、减小碰撞强度等措施,可避免容器出现较大尺寸的泄漏孔,减少池火灾发生概率;采取减缓泄漏速度、控制泄漏范围、迅速合理灭火等应急措施可以减少LNG池火灾危害后果。

液氢槽车氢泄漏风险分析

运用风险管理系统工程原理,采用故障树分析法,对液氢槽车运行过程中的氢泄漏风险进行分析评估。分析了液氢槽车氢泄漏事故机理,明确基本事件32项和中间事件17项,建立了故障树模型。基于故障树的结构分析,求解最小割集,确定了各基本事件的结构重要度。基于专家经验判断的模糊方法预测基本事件概率,采用最小割集计算法近似计算氢泄漏顶事件的发生概率,并计算事件概率重要度,实现故障树的半定量分析,构建基于故障树的液氢槽车氢泄漏风险评价体系。基于事件的结构重要度和概率计算,确定了外力损坏罐体、外热损坏罐体、制止阀卡死、安全阀故障、外力损坏制止阀、泄压失效6项重要风险,并从运营单位日常定检、罐车防护装置设置、液氢储罐失效监测等方面提出了针对性的防范措施以降低液氢槽车氢泄漏风险。

Suggested closed-loop response characteristics for tanker in aerial refueling via mission-oriented evaluation

The flight control law design for tanker should ensure that the closed-loop response can meet the aerial refueling mission requirements. In order to reveal the movement characteristics of the tanker and the handling characteristics of the pilot in aerial refueling, the flight path capture and hold under gust disturbance task is designed as the demonstration maneuver mission to evaluate the flying qualities for tanker in aerial refueling task, which is based on the design requirements of maneuvering tasks used in mission-oriented flying qualities assessment. By analyzing the flight path tracking and holding requirements of the tanker in aerial refueling mission, the relevant parameters that reflect the response characteristics of the tanker in pitch and roll axes are put forward. The ground flight simulation test based on mission-oriented flight quality assessment is conducted, and the test pilot's assessment results based on Cooper-Harper rating and PIO scales are obtained for different flight control law configurations. The suggested requirements of the closed-loop response characteristics of the pitch and roll axes of the tanker are put forward, which can be specifications for the aerial refueling mode flight control design of tanker.

大型油船码头靠船墩导管架结构应力分析

以开敞水域百米水深的30万吨级油船码头靠船墩结构为研究对象,对导管架结构在环境载荷和船舶载荷作用下的应力开展分析。借鉴海洋油气导管架平台结构形式,结合靠船墩导管架结构主要承受水平船舶载荷的特性设计八腿柱、裙桩基础的靠船墩导管架结构形式。采用Ansys有限元软件建立结构分析模型,根据环境条件、载荷组合等参数对靠船墩导管架结构进行4种不同工况下的静力分析。分析结果显示,在船舶靠泊工况下导管架结构位移和应力达最大值,主要出现在近泥面处主腿柱位置,结构应力满足许用应力要求。研究结果表明百米水深大型油船码头采用导管架结构具有一定的可行性,可为深水油船码头结构选型和设计提供一定的参考。