共查询到20条相似文献，搜索用时 218 毫秒
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流速分布及锚链自身刚度对弹性单锚链系统变形和受力的影响 总被引：1，自引：0，他引：1
在锚链系统中,锚链本身的刚度和水流对其作用是影响锚链变形和受力的主要因素。应用分段外推的数值方法,分别对不同刚度和同一弹性锚链在均匀流作用以及同一弹性锚链在不同流速分布(流速在水深方向呈抛物线分布、对数分布)的水流作用下的变形和受力进行了分析和计算,得出了锚链自身的不同刚度及不同流速对锚链的变形及受力的影响情况。结果表明,刚度对锚链受力及变形影响明显,不同流速分布对锚链的偏移量几乎无影响,但对锚链的受力影响较大,选取抛物线型流速分布对锚链安全有利。 相似文献
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从提高锚泊系统收放时效性入手,提出了一种半潜式钻井平台复合式锚泊系统组分配比优化设计方法,旨在尽可能降低复合式锚泊系统的钢链配比长度,提高收放效率。结合锚泊系统设计参数,制定优化设计准则,建立优化分析流程,采用ANSYS-AQWA建立锚泊定位半潜式平台水动力分析模型,获得平台运动参数和锚链动力参数,对平台漂移量、锚链最小安全系数、走锚临界张力、锚链最小卧底长度和起锚力进行无量纲指标分析,并综合考虑张力倾角与预张力对优化结果的影响,获得复合式锚泊系统钢链与钢缆的最优配比关系,确定最优钢链长度为395 m,较原钢链长度缩短225 m,钢链收放时间降低36%,进一步提高锚泊系统收放时效性,并降低平台可变荷载。 相似文献
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《海洋技术学报》2023,(4)
浮标锚链因磨损而断裂会导致浮标丢失,所以针对浮标锚泊系统的研究对锚链设计具有重要意义。为解决锚链系泊力计算方法精度不足和锚链力学简化模型与锚链实际形态不一致的问题,通过VOF （Volume of Fluid） 界面捕捉法建立了三维风、浪耦合流场,基于流体力学计算软件STAR-CCM+对一种滚塑浮标及锚链进行数值仿真计算。在建立双链节锚链物理模型基础上,通过求解浮标在风、浪中的受力及浮标与锚链连接处的受力损失求取锚链系泊力。结果显示,风浪越大,锚链的系泊力损失越大,2、3、4 级海况下浮标阻力损失分别为17.1%、36.6%、55.8%。锚链的双链节受力并非均等,主受力链节在2、3 级海况时承担90%以上的锚链系泊力,次受力链节的系泊力随着总系泊力的增加而增加,可见双链节锚链规格应与单链节相同。 相似文献
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浅水域生存工况下系泊浮筒系统三维运动 总被引：1，自引：0，他引：1
本文提出一个浅水域生存工况下，多锚链系泊浮筒系统三维运动的工程计算模型，对链系采用射的法计算，使其与浮筒运动计算相匹配。对不同的风波流方向及链刚度，计算了浮筒的运动及链力，结果显示本文的模型是合理的。 相似文献
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在较深的海域里设置浮标,如果对它没有特殊要求,一般均可采用单点式锚系。文中介绍了“锚链—化纤绳—锚链”、“加浮球的锚链(或钢丝绳)”、“加浮球的锚链—化纤绳—锚链”等三种组合系留索,并根据海深、浮标受力情况,给出了链长、浮标浮力,浮标的偏移半径、锚的抓住力等计算方法。同时,对锚链、化纤绳、钢丝绳的要求和锚的型式的选择作了一般性的说明。 相似文献
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多锚链系泊浮筒非线性漂移运动的时域模拟 总被引：3，自引：0，他引：3
本文对多锚链系泊浮筒漂移运动的非线性效应进行了讨论。在波浪力和锚链系泊力都是非线性的条件下,对浮筒的运动作时域模拟,并把计算单个系泊锚链流体动力作用的Koterayama W.方法推广到多系泊锚链的情形。计算了规则波和波群中系泊浮筒漂移运动的时间历程,讨论了其运动与波高、频差的关系。可以指出,系泊浮筒系统总漂移运动受锚链流体动力的影响很大;在波群中,其幅值主要受波高支配,与频差的关系较小。 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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系泊系统是半潜式支持平台抵抗恶劣海洋环境作用、限制平台偏移、实现海上定位的重要设备，辐射状多点系泊是常用的布置方式。针对该平台系泊系统开展了设计方法和分析流程研究，阐述了系泊系统配置设计，包括系泊缆的数量、抛出长度、单根系泊缆的刚度、直径、破断负荷、定位锚的型式、最大抓力等；系泊系统的布置设计，包括系泊缆之间的水平夹角、系泊绞车、导缆器、定位锚的位置等；同时归纳风载荷、流载荷以及波浪慢漂载荷的常用估算方法；总结适用于该类平台系泊系统设计的规范要求。将上述方法和流程应用于某型半潜式支持平台系泊系统的开发和设计，采用系泊定位分析程序MIMOSA对该系统的定位能力进行分析，研究了系泊缆形状、夹角等参数随张力的变化特征，同时系泊缆按照船级社的规范要求进行衡准，反复调整和优化系泊系统的配置和布置方式，直至系泊系统满足要求，最终设计出较合适的系泊系统。相关方法、流程和结论为实际工程项目提供重要的设计思路。 相似文献
11.
《中国海洋工程》1998,(1)
A quasi-steady time domain method is developed for the prediction of dynamic behavior of amooring system under the environmental disturbances,such as regular or irregular waves,winds and cur-rents.The mooring forces are obtained in a static sense at each instant.The dynamic feature of the moor-ing cables can be obtained by incorporating the extended 3-D lumped-mass method with the known shipmotion history.Some nonlinear effects,such as the influence of the instantaneous change of the wettedhull surface on the hydrostatic restoring forces and Froude-Krylov forces,are included.Thecomputational results show a satisfactory agreement with the experimental ones. 相似文献
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Fully coupled global analysis of Floating Production Systems, including the vessel, the mooring system and the riser system is described. Design of the system can be a daunting task, involving more than 1000 load cases for global analysis. The primary driver for the mooring system and for the riser system is motion of the vessel. Vessel motions are driven by environmental forces, but are restrained by forces from the mooring and riser systems. Numerical models and procedures that provide accurate and efficient global modeling of the Floating Production System are presented. Both Time Domain and Frequency Domain procedures are included. The accuracy and efficiency of the procedures are illustrated in an example: a large semi with 16 mooring lines and 20 risers. The procedures provide the accuracy and efficiency for use of fully coupled analysis in design of Floating Production Systems from concept selection to final design, installation and operation. 相似文献
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《中国海洋工程》2020,(4)
The study of mooring forces is an important issue in marine engineering and offshore structures. Although being widely applied in mooring system, numerical simulations suffer from difficulties in their multivariate and nonlinear modeling. Data-driven model is employed in this paper to predict the mooring forces in different lines, which is a new attempt to study the mooring forces. The height and period of regular wave, length of berth, ship load, draft and rolling period are considered as potential influencing factors. Input variables are determined using mutual information(MI) and principal component analysis(PCA), and imported to an artificial neural network(NN) model for prediction. With study case of 200 and 300 thousand tons ships experimental data obtained in Dalian University of Technology, MI is found to be more appropriate to provide effective input variables than PCA. Although the three factors regarding ship characteristics are highly correlated, it is recommended to input all of them to the NN model.The accuracy of predicting aft spring line force attains as high as 91.2%. The present paper demonstrates the feasibility of MI-NN model in mapping the mooring forces and their influencing factors. 相似文献
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Ma Peisun Ma Lie Lu Shunshou Associate Professor Shanghai Jiaotong University Shanghai Graduate Shanghai Jiaotong University Shanghai Engineer Shanghai Jiaotong University Shanghai 《中国海洋工程》1991,(4)
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. 相似文献
17.
R.S. Langley 《Ocean Engineering》1984,11(4):381-401
A general method for the dynamic analysis of multi-body offshore structures is presented, being based on a constraint matrix approach. A method of deriving the constraint matrix for a general structure is given, and this is then used to derive the equations of motion of a whole system from those of it's component parts. The response of the system to both first and second order random wave forces is found and then used to calculate the forces and moments in the connecting mechanisms. The structure is assumed to have rigid component parts and a linearised frequency domain analysis method is used, although other methods are discussed. To illustrate it's use, the method is applied to both the SBS and Yoke-CALM design of offshore mooring terminal. 相似文献
18.
New Method for Predicting the Motion Responses of A Flexible Joint Multi-Body Floating System to Irregular Waves 总被引：4，自引：0，他引：4
A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based solutions with experimental results has shown good agreement. 相似文献
19.
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Hull/mooring/riser coupled dynamic analysis and sensitivity study of a tanker-based FPSO 总被引：2，自引：0，他引：2
A computer program is developed for hull/mooring/riser coupled dynamic analysis of a tanker-based turret-moored FPSO (Floating Production Storage and Offloading) in waves, winds, and currents. In this computer program, the floating body is modeled as a rigid body with six degrees of freedom. The first- and second-order wave forces, added mass, and radiation damping at various yaw angles are calculated from the second-order diffraction/radiation panel program WAMIT. The wind and current forces for various yaw angles of FPSO are modeled following the empirical method suggested by OCIMF (Oil Company International Marine Forum).
The mooring/riser dynamics are modeled using a rod theory and finite element method (FEM), with the governing equations described in a generalized coordinate system. The dynamics of hull, mooring lines, and risers are solved simultaneously at each time step in a combined matrix for the specified connection condition. For illustration, semi-taut chain-steel wire-chain mooring lines and steel catenary risers are employed and their effects on global FPSO hull motions are investigated. To better understand the physics related to the motion characteristics of a turret-moored FPSO, the role of various hydrodynamic contributions is analyzed and assessed including the effects of hull and mooring/riser viscous damping, second-order difference-frequency wave-force quadratic transfer functions, and yaw-angle dependent wave forces and hydrodynamic coefficients. To see the effects of hull and mooring/riser coupling and mooring/riser damping more clearly, the case with no drag forces on those slender members is also investigated. The numerical results are compared with MARIN's wave basin experiments. 相似文献