水下系泊监测平台非线性振动稳定性分析

针对水下系泊监测平台在水流涡激作用下的稳定性问题,考虑了浮体在振动过程中的变形,建立了其流固耦合的非线性动力学方程,利用谐波平衡法进行了非线性特性定性分析,Melnikov方法进行稳定性判据研究及影响因素分析,以系统出现混沌状态为稳定性控制条件,重点研究了系泊缆支撑间距对稳定性的影响,并计算出支撑间距的临界值。结果表明,系统稳定性随支撑间距增加而降低,当支撑间距超过临界值后,稍微增加都可能导致系泊监测平台振动偏离振动轨道而造成局部失稳甚至结构破坏。为保证监测平台的稳定性,应增加支撑数量,且支撑的间距不能超过系统发生失稳的临界值。     

Performance Analysis of the Effects of Microgrooved Surface on A Marine Current Turbine with Underwater Mooring Platform

China Ocean Engineering - Marine current turbine (MCT), which is designed for the power supply of underwater mooring platform (UMP), is investigated in this article. To reduce its flow noise, the...     

一种深海系留平台有限元应力分析

深海系留平台是"深海潜标总体关键技术"中最重要的系统组件,是支撑系统的核心,要求有承载深水压力、提供系统浮力和装载仪器设备的能力。针对要求,通过有限元分析软件对深海系留平台的耐压强度进行了深入、细致地分析计算,并经优化完善最终得出深海系留平台可行性分析结论。     

水下滑翔机纵垂面运动姿态分析

在水下滑翔机的设计过程中,为了能够预先估计其水动力特性和操纵特性,避免大量的约束模型实验,需要建立动力学模型以仿真分析水下滑翔机的动力学行为。动力学建模是研究水下滑翔机水动力特性的理论基础,是运动控制的分析依据。通过软件来模拟滑翔机上浮/下潜平衡状态的姿态,并对其进行受力分析得出此姿态对应的理论俯仰角,与实验数据进行了对比,结果基本吻合,为水下滑翔机的设计与控制提供了参考。     

深海SPAR平台系泊系统耦合动力分析

随着海洋石油向深水领域的拓展,SPAR平台以其诸多优点逐渐成为海上油气生产的主流设施。主要研究SPAR与系泊系统间的耦合响应问题,在讨论了浮体在波浪中运动求解方法之后,阐述了如何利用非线性有限元技术对系泊缆索和立管进行动力分析和张力计算,以及浮体与系泊系统耦合计算的相关理论,对浮体和系泊系统耦合计算模型进行了描述。通过对某SPAR进行系泊系统耦合计算和对计算结果的讨论,证明了深海SPAR系泊系统耦合计算的正确性。     

深水半潜式平台锚泊系统风险分析流程研究

为保证深水钻井作业过程中锚泊系统的安全性,降低事故发生率,提高事故应急处置能力,基于故障树、工作安全分析等风险分析方法,并结合锚泊系统自身特性,设计深水半潜式平台锚泊系统风险分析流程。依据钻井作业周期顺序,从抛锚、钻井作业及起锚阶段设计锚泊系统作业风险分析流程。搜集统计锚泊系统常见事故类型,设计走锚风险分析流程,建立走锚事故应急程序。结果表明:所设计的锚泊系统风险分析流程能够弥补现有锚泊系统风险分析的不足,为开展锚泊系统全生命周期内的风险分析提供理论指导,为其它锚泊系统风险相关研究提供参考。     

Stability Analysis of Hybrid-Driven Underwater Glider

Hybrid-driven underwater glider is a new type of unmanned underwater vehicle, which combines the advantages of autonomous underwater vehicles and traditional underwater gliders. The autonomous underwater vehicles have good maneuverability and can travel with a high speed, while the traditional underwater gliders are highlighted by low power consumption, long voyage, long endurance and good stealth characteristics. The hybrid-driven underwater gliders can realize variable motion profiles by their own buoyancy-driven and propeller propulsion systems. Stability of the mechanical system determines the performance of the system. In this paper, the Petrel-Ⅱ hybrid-driven underwater glider developed by Tianjin University is selected as the research object and the stability of hybrid-driven underwater glider unitedly controlled by buoyancy and propeller has been targeted and evidenced. The dimensionless equations of the hybrid-driven underwater glider are obtained when the propeller is working. Then, the steady speed and steady glide path angle under steady-state motion have also been achieved. The steady-state operating conditions can be calculated when the hybrid-driven underwater glider reaches the desired steady-state motion. And the steady-state operating conditions are relatively conservative at the lower bound of the velocity range compared with the range of the velocity derived from the method of the composite Lyapunov function. By calculating the hydrodynamic coefficients of the Petrel-Ⅱ hybrid-driven underwater glider, the simulation analysis has been conducted. In addition, the results of the field trials conducted in the South China Sea and the Danjiangkou Reservoir of China have been presented to illustrate the validity of the analysis and simulation, and to show the feasibility of the method of the composite Lyapunov function which verifies the stability of the Petrel-Ⅱ hybrid-driven underwater glider.     

Dynamic Analysis of Semi-Submersible Production Platform Under the Failure of Mooring Lines

This paper quantitatively studies the transient dynamic response of a semi-submersible production platform with the loss of one or several positioning mooring lines.A semi-submersible platform,production risers,and positioning mooring lines are all included in the numerical simulation.Increased motion of the semi-submersible platform,tension variation of the remaining mooring lines/risers and the risk of mooring line or riser clashing are all investigated through fully coupled time-domain analysis.Combined environmental loads are selected from irregular waves and the steady current varying from very rough to extreme sea conditions.Three dimension radiation/diffraction theories and Morison’s equation are applied to calculate first-order wave force and second-order mean drift force of floating semi-submersible platform.Nonlinear time-domain finite element methods are employed to analyze the behavior of mooring lines and risers.Results show that the failure of mooring lines seriously reduce the platform’s stability performance.The tension of the rest lines is also increased accordingly.Remaining lines which are closer to the failed lines will have larger tension increase to compensate.Line-Line distance provides practical information for the risk of clashing investigation.     

Snap Tension in Mooring Lines of Deepwater Platform

Based on the theory of impact dynamics, the motion equations for a mooring line-floating body system before and after impact loading are established with consideration of the viscoelastic property of mooring lines. The factors that influence the taut-slack conditions of a mooring system are analyzed through classifying the taut-slack regions, which are defined by non-dimensional ratios of displacement, frequency, and damping of the system. The mooring system of Jip spar platform is analyzed, and the snap te...     

Impact Analysis of Air Gap Motion with Respect to Parameters of Mooring System for Floating Platform

In this paper, the impact analysis of air gap concerning the parameters of mooring system for the semi-submersible platform is conducted. It is challenging to simulate the wave, current and wind loads of a platform based on a model test simultaneously. Furthermore, the dynamic equivalence between the truncated and full-depth mooring system is still a tuff work. However, the wind and current loads can be tested accurately in wind tunnel model. Furthermore, the wave can be simulated accurately in wave tank test. The full-scale mooring system and the all environment loads can be simulated accurately by using the numerical model based on the model tests simultaneously. In this paper, the air gap response of a floating platform is calculated based on the results of tunnel test and wave tank. Meanwhile, full-scale mooring system, the wind, wave and current load can be considered simultaneously. In addition, a numerical model of the platform is tuned and validated by ANSYS AQWA according to the model test results. With the support of the tuned numerical model, seventeen simulation cases about the presented platform are considered to study the wave, wind, and current loads simultaneously. Then, the impact analysis studies of air gap motion regarding the length, elasticity, and type of the mooring line are performed in the time domain under the beam wave, head wave, and oblique wave conditions.     

水下无人平台在"马赛克战"中运用构想与分析

根据“马赛克战”作战概念内涵,从作战体系、杀伤效能、作战力量构成等方面研判其对我海战的威胁,并在此基础上详细提出了水下无人平台的基本作战构想和主要运用方法;分析了 UUV 与 PUS 相关平台总体、集群协同、通信组网、水下态势感知等主要关键技术。为研究“马赛克战”对海战的影响及其对策提供了一定的理论参考价值。