Dynamic Analysis of Turret-Moored FPSO System in Freak Wave

Freak wave is the common wave which has significant wave height and irregular wave shape, and it is easy to damage offshore structure extremely. The FPSOs（Floating Production Storage and Offloading） suffer from the environment loads, including the freak wave. The freak waves were generated based on the improved phase modulation model, and the coupling model of FPSO-SPM（Single Point Mooring） was established by considering internal-turret FPSO and its mooring system. The dynamic response characteristics of both FPSO and SPM affected by the freak wave were analyzed in the time domain. According to the results, the freak waves generated by original phase modulation model mainly affect the 2nd-order wave loads. However, the freak waves which are generated by random frequencies phase modulation model affect both 1st-order and 2nd-order wave loads on FPSO. What is more, compared with the irregular waves, the dynamic responses of mooring system are larger in the freak waves, but its amplitude lags behind the peak of the freak wave.

Investigation of Performance of Turret Assembly in Inboard Turret Mooring System

To fulfil the need of development of offshore oil floating production system, the performance of turret assembly in an inboard turret mooring system has been investigated in the paper. By means of systematic evaluation, the optimal structure of the turret for single-point mooring systems has been determined. Through model tests of a turret mooring system, several groups of data such as forces, moments and displacements under different environmental conditions have been obtained. Stresses and strains of the turret structure have been calculated by means of the finite element method corresponding to the situation in the model experiment. The study shows that the selected turret structure and the designed turret assembly are technically feasible.

Failure Statistics Analysis Based on Bayesian Theory: A Study of FPSO Internal Turret Leakage

The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure models are difficult to establish through traditional statistical methods. Hence, the calculation of the occurrence probability of small sample events is often met with great uncertainty. In this study, the Bayesian statistical method is implemented to analyze the oil and gas leakages of FPSO internal turret, which is a typical small sample risk but could lead to severe losses.According to the corresponding failure mechanism, two Bayesian statistical models using the Weibull distribution and logarithmic normal distribution as the population distribution are established, and the posterior distribution of the corresponding parameters is calculated. The optimal Bayesian statistical model is determined according to the Bayesian information criterion and Akaike criterion. On the basis of the determined optimal model, the corresponding reliability index is solved to provide basic data for the subsequent risk assessments of FPSO systems.

Design Curves for Mooring Lines of Turret Mooring Systems

This paper presents a series of design curves to aid in the selection of turret mooring systems for tankers based Floating Production Storage and Offloading (FPSO) systems. These curves are appropriate to water depths ranging from 100 m to 600 m. The curves can be used as a preliminary design tool, allowing the designer to quickly evaluate alternative mooring system configurations, including the number of mooring lines, the characteristics of chain and wire rope to be deployed and the. initial tension. With a knowledge of the total environmental force and vessel motion characteristics, the designer can determine the appropriate system for closer evaluation.

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.

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.

国外转塔式光电瞄准吊舱技术发展分析

对国外转塔式光电瞄准吊舱进行了划代,介绍了典型第三代吊舱的主要技术特点,定义了衡量光电吊舱集成度的四个评价标准:通光孔径与舱体直径之比、通光孔径的立方与系统重量之比,舱体直径的立方与系统重量之比以及有效载荷重量与系统重量之比,实现了从宏观层级对性能相近的光电瞄准吊舱功能密度或技术水平的定量评价。介绍了国外典型装备的发展状况,重点针对美国MTS-B吊舱、土耳其ASELFLIR350吊舱及之后的400/500、加拿大MX-15D吊舱、法国EUROFLIR410吊舱和德国ARGOS II HDT等典型产品进行了对比分析,介绍了各自的技术风格、特点和重要载荷;通过正向设计评估验证了MTS-B前置望远系统的性能指标和ASELFLIR350的光学有效载荷;总结了现代光电瞄准吊舱的几大趋同化技术特点:多波段共孔径折反式主系统+旁轴小口径次系统的光机架构正取得共识、多种波段的激光探测技术日益倾向主动光学方向、基于多轴多框平台和快反镜相结合的复合轴控制技术正在普及、详查探测更注重目标细节区域增强、多波段图像融合信息处理技术在显控中越发重要。

深水海上浮式生产储油轮内转塔单点系泊系统柔性立管通道与悬挂结构设计

深水油气开采中带内转塔单点系泊系统的海上浮式生产储油轮(FPSO)占据主导地位。以1艘深水FPSO内转塔单点系泊系统为例,介绍了柔性立管通道的总体布置原则、通道与悬挂相关的设计要点,考虑了百年一遇在位的极端环境和海上临时悬挂安装的设计工况,依据法国BV船级社规范进行了立管通道和悬挂结构的计算分析,给出内转塔单点系统立管通道的相关设计方法和流程。

连铸大包回转支承状态劣化的几种数字表征

连铸大包回转支承状态监控目前有传动电机电流监控、润滑油品理化指标检测以及应力波检测等几种有效方法,分别采用这几种方法对回转支承整个劣化过程进行了数据采集和分析,并通过现场解体后的现象和数据对几种方法预判结果进行了验证,可为低速重载类设备状态维护提供参考。

内转塔式单点系泊系统解脱施工方案研究

南海某油田浮式生产储存卸油船舶(FPSO)为内转塔式单点系泊系统(STP),以该内转塔式单点系泊系统解脱作业为例,开展适用于中国南海海域FPSO解脱施工方案研究,分析解脱施工中关键作业节点的施工方法,为今后南海海域FPSO解脱施工提供参考。

YB518型盒外透明纸包装机折叠转塔离合器调校工装的研制

为解决YB518型盒外透明纸包装机折叠转塔离合器在挤烟时不能及时脱开、安装时扭矩调整困难等问题,研制一种可以实现转塔离合器定量调校的工装。通过使用ANAYS Workbench软件对工装的重要零件压力弹簧进行有限元模拟仿真,确定弹簧材料的选择。利用故障停机率拟合线得出转塔离合器调校时的最佳扭矩值为35N·m。使用该工装对YB518型盒外透明纸包装机折叠转塔离合器进行调校后,转塔离合器脱开率由29.54%提高至94.54%,挤烟平均停机时间缩短了64.71%,降低了设备维修保养时的劳动强度,提高了设备生产效率。此外,通过调节直径,该工装能够适用于多种尺寸型号的转塔离合器,实用性强。

复合磨床砂轮架模态分析与试验研究

基于赫兹接触理论建立了轴承滚动结合部接触模型,采用弹簧阻尼单元代替轴承滚子结合部,在ABAQUS有限元分析软件建立复合磨床砂轮架转塔有限元模型,对转塔结构进行模态分析。利用LMS结构试验系统对转塔结构进行模态测试与分析。试验表明,采用弹簧阻尼单元模拟轴承滚动结合部的有限元模态分析与动态试验结果吻合,验证了该方法的可行性。弹簧阻尼单元替代轴承可以减小建模难度,并为砂轮工作转频和转塔结构优化提供参考依据。

连铸钢包回转台在线修复工艺的开发及实践

钢包回转台是连铸的关键设备,本文分析了某厂连铸钢包回转台钢包接收鞍座裂纹产生的原因,针对裂纹在线修复难点,制作了辅助加热工具,确定了结构补强方案和施焊工艺,保证了在线加工的精度,并通过了实践验证。

LF精炼炉钢包回转台驱动系统设计与分析

LF炉是整个钢铁精炼工艺过程中最为重要的设备,具有脱硫、脱氧,微调钢水成分的作用,对提高钢水品质具有重要作用;是每个钢企生产优钢特钢的必备设备。现有LF精炼炉主要结构型式分为双车式、回转台式以及电极旋转式。回转台式LF炉其特点是利用回转台的自转将钢水从等待工位转运钢水至冶炼工位进行冶炼;回转台式LF炉具有占地面积小,使用安全可靠,维护保养工作量小,效率高等优势。回转台作为LF精炼炉的重要组成设备,对整个精炼炉安全运行有着重要的作用;而回转台的平稳运行又取决于驱动装置设计的可靠性。针对回转台的驱动装置设计进行分析。通过对回转台驱动系统基础数据的计算、电机和减速机的选型,提出一个安全、可靠的设计方案,以便其他设计者进行参考。

涡流发生器对半球形激光转塔跨声速流场影响数值研究

激光转塔的跨声速绕流场使得机载激光平台面临着严峻的气动光学挑战。为对激光转塔的跨声速流场被动控制提供基本的理论支撑,本文利用了改进亚格子尺度的改进延迟脱体涡模拟(IDDES)方法,针对细长圆柱的针状涡流发生器,对跨声速条件下半球形机载激光转塔的绕流场进行了流动控制数值研究。结果表明,针状涡流发生器引入了明显的二次流特征,削弱了来流能量,导致激光转塔顶部激波强度受到影响,进而影响了激光转塔尾迹区的分离泡尺寸;激光转塔尾迹的横向摆动和纵向波动特征的时空特性并未受到涡流发生器的明显影响,而动态模态分解(DMD)结果指出了当涡流发生器存在时,激光转塔尾迹的纵向波动模态能量具有明显的衰减,合理地对应了尾迹分离泡形态的改变,揭示了本文研究的涡流发生器对激光转塔尾迹分离区的抑制作用,为以被动控制方法来抑制激光转塔气动光学效应提供了依据。

Numerical Investigation on the Hydrodynamic Diference Between Internal and External Turret-Moored FLNG

Motion responses of the floating liquefied natural gas(FLNG)hull and the mooring loads in a 100-year return environmental condition are predicted with the help of the well known coupled dynamic analysis code DeepC.A ship-shaped turret-moored FLNG moored by 4×3 chain-polyester-chain lines in 1.5 km depth of water is studied.Two types of turrets such as internal and external turrets,resulting from diferent locations of the turrets,are adopted respectively in the numerical simulations.Motion responses of the FLNG hull and forces of the mooring lines obtained from the internal turret case and external turret case are compared with each other.Significant diferences are obtained.Statistic analysis is also used to analyze the comparison results,and efects of the turret location on the FLNG hydrodynamic characteristics are summed up.The conclusion regarding the hydrodynamic diferences between internal and external turret-moored FLNG systems would provide help for design of the FLNG system.

航空光电转塔技术发展综述

光电转塔广泛搭载于各类航空平台,通过集成多个谱段的成像传感器实现全天时成像侦察,在执行各种任务时发挥着越来越重要的作用,世界各主要军事强国均发展了先进的光电转塔产品。通过对航空光电转塔发展历程的简要回顾及当今世界各国同类产品进行分析,对该领域国外发展现状、主要产品性能及参数进行阐述,从系统设计、伺服技术、结构技术、光学技术、新体制探测成像、图像处理、人工智能、处理器性能等方面,对其主要技术发展特点及趋势进行提炼总结,并对需要重点关注的关键技术进行简要评价,以期对国内航空光电转塔的未来发展思路提供参考。

某转塔舱运输辅助支撑机构设计与分析

提出了一种用于某偏心转塔舱运输的辅助支撑机构,采用电动缸驱动的连杆机构,并利用连杆的死点位置有效提高了机构的负载能力,实现了机构的小型化及轻量化设计。首先对该转塔舱运输过程中的载荷及连杆机构基本原理进行分析,并根据摩擦因数、导向段弧形导轨长度及连杆自锁角度等参数,对机构进行自锁分析;然后对连杆机构进行结构设计,并根据具体尺寸参数对机构进行运动学及动力学分析;最后进行NX动力学分析、有限元仿真及试验,验证了所提连杆式辅助支撑机构的运动能力及承载能力,证明了该辅助支撑机构设计的可行性与实用性。

运用FANUC信号追踪功能解决电气故障的方法研究

设备电气故障通常为软故障,原因不易发现,日常维修过程中凭借经验判断费时费力、准确度低。当前工业发展迅速,生产节拍要求越来越高,设备出现故障后需要快速精准恢复,给设备维护人员带来挑战。文章以数控车床CK7530F刀塔故障为例,结合刀塔电气控制原理,利用FANUC系统信号追踪功能,总结出一套针对电气故障维修的思路和方法,有利于数控设备维护工作效率的提高。

基于ANSYS的矿用掘进机回转台振动疲劳分析方法

掘进机截割过程易受到强冲击载荷而导致回转台产生振动疲劳现象,对作业的可靠性和稳定性影响较大。经分析掘进机回转台的作业原理,依据Palmgram-Miner疲劳判断法则,利用ANSYS仿真软件对回转台振动疲劳情况进行分析。结果表明:回转台X轴向的振动对回转台疲劳损伤影响较大,通过减振能够较好的提升回转台的整体寿命;回转台与油缸连接的4个销轴位置易产生疲劳损坏现象,最小循环载荷为38965次;仿真结果与现实情况相一致,分析方法具备一定的合理性与可行性,能够作为回转台结构优化和改进的参考依据。