共查询到19条相似文献，搜索用时 646 毫秒
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研究复杂海底地形对脐带缆深水安装过程中的力学特性影响,对提高脐带缆深水安装的安全性与稳定性有较大意义。通过建立具有不同坡度、隆起高度以及低洼深度的海床地形模型,分析在不同地形参数下脐带缆深水安装时的应力响应,并对不同参数下的等效应力与接触压强对比,探讨了海底地形对脐带缆深水安装的影响。研究结果分析表明:海床坡度对脐带缆的最大等效应力与接触压强影响不大;隆起区域对脐带缆的安装过程的影响较大,隆起高度的增加使最大等效应力明显增大,且易超过脐带缆的最大许用等效应力;低洼区域的脐带缆与隆起区域相似,低洼深度的增加最大等效应力明显增大,隆起区域与低洼区域的触地点处的接触压强最大。 相似文献
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在频域和时域内研究对等分布式系泊和分组式系泊2种系泊模式对Spar平台运动性能的影响,并分析单根系泊缆破断失效后平台运动性能的变化。首先建立Spar平台的三维水动力模型,通过在平台柱体导缆孔处指定预张力、倾角和刚度来模拟系泊系统的影响;然后采用三维势流理论进行浮体水动力计算,获得Spar平台运动响应的传递函数等水动力参数;最后根据实际海况资料,在平台生存工况下,进行Spar平台在完好系泊和单根系泊缆破断失效状态下运动响应的短期预报,并在时域内进行耦合分析,研究平台运动响应和系泊缆张力变化情况。研究结果对Spar平台系泊系统设计和平台设计前期运动性能研究有参考意义。 相似文献
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为了探究钻井支持平台及生产平台组成的复杂多浮体耦合系统在近距离靠泊状态下的相对运动情况,基于多浮体三维势流理论及时域耦合分析方法,计算了半潜式钻井支持平台和张力腿(TLP)生产平台耦合系统在三种不同环境方向,即迎浪、斜浪、横浪下两平台的相对运动和平台间连接栈桥的运动响应,为平台运动分析和栈桥设计提供指导。并将计算结果与水池模型试验结果进行对比,验证了数值方法的可靠性。为进一步了解多浮体间耦合水动力的影响,计算了该近距离靠泊系统在不考虑浮体间水动力相互干扰下的运动响应。研究表明除在横浪作用外,其他环境条件下的多浮体水动力干扰作用明显,对浮体运动响应的影响不可忽略,且有效波高在小范围内变化时,平台间的相对运动幅值基本与其呈线性关系。 相似文献
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在深海采矿车布放回收中,准确预报脐带缆在底部自由悬垂边界条件和顶部波浪载荷随机激励等共同影响下的动力响应是关键点之一。基于三维势流理论与集中质量法,结合水面支持船运动和海流联合激励,对深海布放回收中脐带缆的顶端张力等力学特性进行研究。结果表明：在布放回收过程中,轴向张力在结构载荷中占主要成分;由波浪引起的轴向张力极值与均值差距最大可达到54%;轴向张力的频谱存在双谱峰,分别为 0.14 Hz的主峰和0.10 Hz 的次峰;当浪向角为180°时,轴向张力处于峰谷。 相似文献
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脐带缆是连接平台或浮式生产系统与海底油井的控制管缆,缆芯由管单元、光纤单元、电缆单元、以及填充单元组装而成,缆体外层由铠装钢丝螺旋缠绕和聚合物护套组成。基于ANSYS有限元软件,建立无铠装含填充的钢管脐带缆三维有限元模型,在自由端可扭转、不可扭转约束条件下,计算模型的拉伸刚度,将拉伸刚度的数值模拟与理论结果进行对比,验证有限元模型的正确性;分析比较含填充与不含填充两种截面形式脐带缆模型的力学性能,结果表明:填充单元、拉伸率对脐带缆模型的拉伸刚度、最大等效应力模拟结果均有影响。 相似文献
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FSRU码头系泊模型实验与数值模拟研究 总被引：1，自引：0，他引：1
FSRU在恶劣环境条件下的作业和安全停靠性能与系泊缆张力、靠垫挤压应力、船体6自由度运动等参数有关。针对FSRU码头处海洋环境条件,进行FSRU不同装载状况的模型实验,获得FSRU的6自由度运动及其系泊载荷的动力特性。基于三维辐射和绕射理论,使用Sesam软件进行频域计算,以此为基础在相应海洋环境条件下进行时域耦合分析,获得FSRU 6自由度运动、系泊载荷、靠垫应力等参数的响应时历。结果表明:30%装载、横浪条件下FSRU的运动响应最大,系泊缆张力未达到破断值,靠垫压力超过其压缩60%时的载荷;模型实验对FSRU运动响应和系泊缆张力的预测结果可信,靠垫受力情况需要数值仿真进行辅助研究。 相似文献
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On the motions of the underwater remotely operated vehicle with the umbilical cable effect 总被引：1，自引：0，他引：1
In this paper, a hydrodynamic model is developed to simulate the six degrees of freedom motions of the underwater remotely operated vehicle (ROV) including the umbilical cable effect. The corresponding hydrodynamic forces on the underwater vehicle are obtained by the planar motion mechanism test technique. With the relevant hydrodynamic coefficients, the 4th-order Runge–Kutta numerical method is then adopted to solve the equations of motions of the ROV and the configuration of the umbilical cable. The multi-step shooting method is also suggested to solve the two-end boundary-value problem on the umbilical cable with respect to a set of first-order ordinary differential equation system. All operation simulations for the ROV including forward moving, ascending, descending, sideward moving and turning motions can be analyzed, either with or without umbilical cable effect. The current effect is also taken into consideration. The present results reveal that the umbilical cable indeed significantly affects the motion of the ROV and should not be neglected in the simulation. 相似文献
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In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses, the experimental study on VIV of bond umbilical cable(BUC) and un-bond umbilical cable(UBUC) was carried out in an experimental tank. A current generator in the laboratory simulated the uniform current, and the current velocities were observed in real time by using a Doppler Velocimeter. In addition, different sizes of top tension were applied to the umbilical cable model. The VIV responses of the umbilical cable model were measured by using Fiber Bragg grating(FBG) strain sensors. The displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition method. In this paper, the traveling wave characteristics, the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are studied. The experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of VIV. The UBUC appears the traveling wave sooner than BUC, but its standing wave characteristics are more obvious than those of BUC at high velocities. Compared with BUC, the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner, but has narrower bandwidth in the "lock-in" state. The level of fatigue damage of BUC was approximately the same as that of UBUC. 相似文献
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浮式防波堤充分利用波能在水深方向的分布特性,在满足工程消浪要求的同时对海域水沙交换影响较小,且能够快速布置,在某些实际工程有一定应用前景。为了深入了解波浪作用下浮式防波堤的动力响应,基于OpenFOAM标准求解器olaFlow,在刚体运动求解计算中植入锚链求解模块MOODY(mooring cable dynamics),实现了基于重叠网格方法的浮体运动与锚链受力耦合求解,建立了锚链系泊浮式防波堤动力响应的二维数值模型。利用该数值模型对锚链系泊单方箱浮式防波堤在波浪作用下的透射系数、运动响应、锚链张力进行了模拟,并和相关试验结果进行了比较。结果表明,模型能够准确模拟二维波浪和浮式防波堤的相互作用,并用于三维模型的改进。 相似文献
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An integrated hydrodynamics and control model to simulate tethered underwater robot system is proposed. The governing equation of the umbilical cable is based on a finite difference method, the hydrodynamic behaviors of the underwater robot are described by the six-degrees-of-freedom equations of motion for submarine simulations, and a controller based on the fuzzy sliding mode control (FSMC) algorithm is also incorporated. Fluid motion around the main body of moving robot with running control ducted propellers is governed by the Navier–Stokes equations and these nonlinear differential equations are solved numerically via computational fluid dynamics (CFD) technique. The hydrodynamics and control behaviors of the tethered underwater robot under certain designated trajectory and attitude control manipulation are then investigated based on the established hydrodynamics and control model. The results indicate that satisfactory control effect can be achieved and hydrodynamic behavior under the control operation can be observed with the model; much kinematic and dynamic information about tethered underwater robot system can be forecasted, including translational and angular motions of the robot, hydrodynamic loading on the robot, manipulation actions produced by the control propellers, the kinematic and dynamic behaviors of the umbilical cable. Since these hydrodynamic effects are fed into the proposed coupled model, the mutual hydrodynamic influences of different portions of the robot system as well as the hydrological factors of the undersea environment for the robot operation are incorporated in the model. 相似文献
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A.K. Jain 《Ocean Engineering》1997,24(7):577-592
Among the compliant platforms, the tension leg platform (TLP) is a vertically moored structure with excess buoyancy. The TLP is designed to behave in the same way as any other moored structure in horizontal plane, at the same time inheriting the stiffness of a fixed platform in the vertical plane. Dynamic response analysis of a TLP to deterministic first order wave forces is presented, considering coupling between the degrees-of-freedom surge, sway, heave, roll, pitch and yaw. The analysis considers nonlinearities produced due to changes in cable tension and due to nonlinear hydrodynamic drag forces. The wave forces on the elements of the pontoon structure are calculated using Airy's wave theory and Morison's equation ignoring diffraction effects. The nonlinear equation of motion is solved in the time domain by Newmark's beta integration scheme. The effects of different parameters that influence the response of the TLP are then investigated. 相似文献
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Study on Model Tests and Hydrodynamic Force Models for Free Spanning Submarine Pipelines Subjected to Earthquakes 总被引：1，自引：0，他引：1
A test rig is built to model the dynamic response of submarine pipelines with an underwater shaking table in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, China. Model tests are carried out to consider the effects of exciting wave directions and types. Based on the experimental results, two hydrodynamic force models derived from Morison equation and Wake model are presented respectively. By use of hydrodynamic force models suitable for free spanning submarine pipelines under earthquakes, discretized equations of motion are obtained and finite element models are established to analyze dynamic response of free spanning submarine pipeline subjected to multi-support seismic excitations. The comparison of numerical results with experimental results shows that the improved Morison and Wake hydrodynamic force models could satisfactorily predict dynamic response on the free spanning submarine pipelines subjected to earthquakes. 相似文献